control concepts surge protective device training manual

7/25/2019 CONTROL CONCEPTS SURGE PROTECTIVE DEVICE TRAINING MANUAL

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CONTROL CONCEPTS

SURGE PROTECTIVE DEVICE

TRAINING MANUAL


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INDEX

SECTION DESCRIPTION

I THEORY

II CLASSIFICATION of

POWER PROBLEMS

III STANDARDS

IV PRODUCTS

V SELECTION of PRODUCTS

VI TYPICAL QUESTIONS


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(I.) THEORY

Where does electrical power come from?

Electrical power is generated in a utility power plant, producing electric current with extremely high

voltages (up to 22,000 volts). High voltages are required for transmission over long distances to reduce powerlosses that occur during transmission.

Transformers in the utility plant increase the generated voltage to the limit of the transmission lines

(typically in the area of 140,000 volts but potentially as high as 700,000 volts).

Transmission line voltages are reduced through transformers to a more suitable range (around 34,000

volts) for distribution to substations, where voltages are reduced again to between 2,400 and 14,400 volts.

Many industries require power at these voltages, while business offices, homes, stores and other

facilities require power at lower voltages, usually from 120 to 240 volts. These voltage levels are obtained

through pole transformers feeding the various facilities.

What are some of the typical nominal voltages and source configurations we would deal with?

Service Entrance/Distribution Area: 277/480 Three-Phase Wye, 120/208 Three-Phase Wye, 480 Three-Phase

Delta

Office/Residential/Distribution Area: 120/240 Single Phase or Split Phase

International Service Entrance/Distribution Area: 230/400 Three-Phase Wye, 346/600 Three-Phase Wye


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SOURCE CONFIGURATIONS

NOMINAL OPERATING VOLTAGE MODEL

VOLTAG

L-N L-L L-G CODE

Single Phase L-N, 2W+G

Single Phase L-L, 2W+G

Single Phase L-L, 2W+G

Split Single Phase, 3W+G

*Three Phase Delta, 3W+G

*Three Phase Delta Hi-Leg, 4W+G

Three Phase Wye, 4W+G

*Three Phase Wye, 3W+G

100 N/A 100 100N110 N/A 110 110N

120 N/A 120 120N

230 N/A 230 230N

277 N/A 277 277N

346 N/A 346 346N

N/A 208 208 208L

N/A 240 240 240L

N/A 400 400 400L

N/A 480 480 480L

N/A 600 600 600L

N/A 208 120 208A

N/A 240 120 240A

N/A 400 230 400A

N/A 480 277 480A

N/A 600 346 600A

100 173 100 100S

110 190 110 110S

120 208 120 120S

230 400 230 230S

277 480 277 277S

346 600 346 346S

N/A 208 208 208D

N/A 240 240 240D

N/A 400 400 400D

N/A 480 480 480D

N/A 600 600 600D

A-N/B-N/C-N L-L A-G/B-G/C-G

120/208/120 240 120/208/120 240H

240/277/240 480 240/277/240 480H

100 173 100 100Y

110 190 110 110Y

120 208 120 120Y

230 400 230 230Y

277 480 277 277Y

346 600 346 346Y

N/A 208 120 120YN/A 400 230 230Y

N/A 480 277 277Y

N/A 600 346 346Y

* Please note: The Line-to-Ground voltage in a three wire Wye system differs from that of a Delta system

Inherently, the SPD is a voltage sensitive device. Therefore, to insure proper operation it is imperative to

correctly identify the appropriate voltage configuration when ordering. Consult factory with any

questions.


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5

You will hear the term AC Signal mentioned frequently; what does this mean?

AC orAlternating Currentis an electrical current that changes in both magnitude and

direction. The voltage and current is produced by alternating current generators in a

sinusoidal waveform or sine wave.

AC voltage alternates in both a positive and negative direction, one completeshiftfrom

positive to negative is referred to as a cycle or 360 electrical degrees.

The frequencyof the sine wave is the number of complete cycles (positive to negative

shift) that occurs in one second. The common unit of measurement for frequency is hertz

(HZ). In the United States we commonly refer to a frequency of 60 hertz where on cycle

occurs in 1/60th

of a second.

Our products are designed to address many of the disturbances that occur on an AC

signal.


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(II.) CLASSIFICATION OF POWER PROBLEMS

What are some of the typical power disturbances our product/s will address?

We attenuate high frequency noise (3 kHz to 50 MHz) and clamp transients.

What causes high frequency noise?High frequency noise is the most common power problem found in any facility. It is

defined as a low to high amplitude, low current, and high frequency disturbance.

Approximately, 99% of all power problems can be attributed to noise. Internally, noise

can be generated by any switching type power supply, motor controllers, arcing contacts

(when equipment is turned on and off), etc. Externally, noise may be generated by

lightning, utility switching, etc.

What causes transients?

Similar to high frequency noise transients can be generated both externally and internally.

External sources of transients are lightning, utility line work, system faults, etc. Internally,

transients may be generated by motors, arc welders, transfer switches, etc. While thefrequency of occurrence may not be as high as noise, the effects are more sudden and

devastating. A transient is defined as high voltage/high current, low frequency

disturbance.

What conduction path does high frequency noise or transients take to get to my

equipment?

The power disturbances can occur in both normal (line to neutral and or line to line) and

common (line to ground and or neutral to ground) modes. However, common mode

transients or noise, typically is generated by lightning, radio transmission, poor grounding

and shielding to name a few. Normal mode disturbances commonly occur due to utility

grid switching, computer operation, motor speed controllers, etc.


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Power Conditions Definitions Causes Product to

Recommend

Common Mode Noise(line to ground and/or neutral

to ground)

Low to high amplitude,

low current, and high

frequency disturbances.Consists of impulses

(amplitude of up to 50

volts) and EMI/RFI noise

(amplitude of millivolts

to several volts) -

measured to ground -

superimposed on the

power conductor.

Radio transmission

Normal computer

operationArcing contacts

(equipment turning

on and off)

Lightning

Poor grounding

and shielding

Series

Product

Islatrol Elite

Islatrol Plus

Islatran

Normal Mode Noise(line to neutral and/or line to

line)

Low to high amplitude,

low current, and high

frequency disturbances.

Consists of impulses(amplitude of up to 50

volts) and EMI/RFI noise

(amplitude of millivolts

to several volts) -

measured line to neutral

or line to line -

superimposed on the

power conductor.

Normal computer

operation

Switching power

supplies

Motor speed

controllers

Islatrol

Islatrol Elite

Islatrol Plus

Islatran

Impulses and

Transients

High voltage/high

current, low

frequencydisturbance.Amplitude of 50 volts too

as high as several

thousand volts. Duration

is typically less than a

millisecond.

Switching loads on

and off.

Utility switchingLightning

Fault clearing

IslaGuard

(IH,IM,IL)Islatrol Elite

Islatrol Plus

Islatran

Harmonics A continuous distortion

of the normal sine

wave, at frequencies

lower than 3 kHz.

Switching loads

Normal computer

operation

Nothing- our

products are

designed to

attenuate high

frequency

disturbances.


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Power Conditions Definitions Causes Product to

Recommend

Overvoltages A high-voltage

condition on one or

more phases. Voltages

above 110% of nominalvoltage. Duration is

several cycles (a few

seconds).

Utility switching

Rapid load

reduction

Nothing in

our product

line. The

customerneeds a

voltage

regulator.

Undervoltages or

Brownouts

A low-voltage

condition on one or


below 80-85% of

nominal voltage.

Duration is several

cycles (a few seconds).

Ground faults

Starting large

loads

Inadequate power

system capacity

Utility switching

Utility equipment

failureLightning

Nothing in

our product

line.The

customer

needs a

voltage

regulator

Swells or Surges A high-voltage

condition on one or


above 110% of nominal

voltage. Duration is one

cycle or less.

Utility switching

Rapid load

reduction

Nothing in

our product

line. The

customer

needs a

voltage

regulator.

Sags or Dips A low-voltage

condition on one ormore phases. Voltages

below 80-85% of

nominal voltage.

Duration is greater than

one cycle.

Ground faults

Starting largeloads

Inadequate power

system capacity

Utility switching

Utility equipment

failure

Lightning

Nothing in

our productline.The

customer

needs a

voltage

regulator

Power Outage,

Blackout, or Power

Cut

A zero-volt condition

lasting longer than a

half-cycle.

Ground Faults

Equipment Failure

Accidents

Utility equipmentfailure

Lightning

Complete line

ofSingle

Phase UPS


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(III.) Standards

Canadian Standards Association (CSA): Consists of a series of Canadian electrical

requirements. Including surge suppression, electrical code, filtering, and surge

arrestors.

American National Standards Institute and Institute of Electrical and Electronic

Engineers (ANSI/IEEE C62.11, 62.41, C62.45):

C62.11- IEEE Standard for Metal Oxide Surge Arresters for AC Circuit

Power

C62.41- IEEE Recommended Practice on Surge Voltages in Low-Voltage

(600 volts and less) AC Power Circuits. : Characterizes electrical systems in

which a surge exists including location categoriesand their applicable

waveform.

Location Categories C62.41

The protectors ability to survive and to achieve a suitable let thru voltage depends on the

size of the applied transient. This in turn depends on the protectors location. As

mentioned, C62.41 outlines three location categories, those categories defined in the

following manner:


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Location Categories C62.41 Continued:

Each category is broken into sub categories (A1, A2, A3, etc.) with waveforms and

voltage/ ampere levels assigned to each. The following is a list of the waveforms defined

in C62.41:

Category Volts/Amps Wave Forms*C3 - Service Entrance 20 kV / 10 kA Bi-wave

1.2 x 50 s, 8 x 20 s

C2 - Service Entrance 10 kV / 5 kA Bi-wave

1.2 x 50 s, 8 x 20 s

B3/C1 - Service Entrance 6 kV / 3 kA Bi-wave

1.2 x 50 s, 8 x 20 s

B2 - Main Distribution

Feeders

4 kV / 2 kA Bi-wave

1.2 x 50 s, 8 x 20 s

B1 - Main Distribution

Feeders

2 kV / 1 kA Bi-wave

1.2 x 50 s, 8 x 20 sB3 - Load Centers/Sub-

Distribution Panels

6 kV / 0.5 kA Ring Wave

.5s - 100 kHz

B2 - Load Centers/Sub-

Distribution Panels


.5s - 100 kHz

B1 - Load Centers/Sub-

Distribution Panels


.5s - 100 kHz

A3 - Wall Receptacles 6 kV / 0.2 kA Ring Wave

.5s - 100 kHz

A2 - Wall Receptacles 4 kV / 0.13 kA Ring Wave

.5s - 100 kHz

A1 - Wall Receptacles 2 kV / 0.07 Ring Wave

.5s - 100 kHz

* Category used for the multiple hit test (or endurance test)

What exactly do these waveforms look like?

1.2 x 50 us 8 x 20 us

.5 us x 100kHz


11/23

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C62.45- Guide On Surge Testing for Equipment Connected to Low-Voltage

(600 volts and less) AC Power Circuits. : Test procedures for surge

suppressors are defined.

Federal Information Processing Standards Publication 94 (FIBS PUB 94) - Aguideline on electrical power for ADP installations (US Department of Commerce,

National Bureau of Standards)

National Electrical Manufacturer Association (NEMA LS-11992): A document that

defines specification parameters and their definitions. The document also mentions

test and evaluation procedures.

National Fire Protection Association (NFPA 20, 70, 75 and 780)

NFPA 20refers to the standard for the installation of Centrifugal Fire Pumps.

Mentions C62.11 and the requirement for suppression.

NFPA 70: This is the National Electric Code (See NEC listed below).

NFPA 75Standard for the Protection of Electronic Computer/Data Processing

Equipment

NFPA 780Lightning Protection Code: Covers requirements for lightning

protection for various types of structures including structures containing

flammable gases and vapors.

National Electric Code (NEC): Code that applies to installation of equipment-

includes specific rules regarding wire sizes, fusing, grounding, etc.)

Underwriters Laboratories (UL 1449 and UL 1283)

UL 1283refers to safety testing of filters or products that act to filter.

UL 1449refers to UL safety test often used to compare an SPDs ability to

clamp a transient

First Edition

Effective August 1985

Second Edition

Effective August 1997 *Effective 1998

(New Products) (Current Products Postponed until Aug. 1998)

UL 1449 consists of the following:

Measured Limited Voltage TestPermanently Connected

- 6kV, 1.2/50s open circuit voltage

- .5kA, 8/20s short circuit current

- Test with 6 leads external to enclosure

Surge Current Test

Permanently Connected

- 20kV, 1.2/50s open circuit voltage


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- 10 kA, 8/20 s short circuit current

- Operation of O.C. protection is acceptable

-

UL 1449 Continued:

Withstand Test- 125% Rated voltage for 7 hours

Abnormal Over-Voltage Limited Current

- Simulated lifted neutral

- Full phase voltage

- Limited current @ .125A, .5A, 2.5A, 5.0A

Abnormal Over-Voltage High Current

- Simulate miswiring

- Full phase voltage

- Rated Fault Current 5kA minimum

- TVSS instruction manual to define conditions of application

International Electrotechnical Commission (IEC 801): Electromagnetic compatibility

for industrial and data process, measurement and control equipment.

International Standards Organization (ISO) Company certified ISO 9001: Quality

standard

Military Standards (MIL-220A): A military standard that defines a method of testing a

device's noise attenuation capability.

NEMA Enclosure Standards:

NEMA Type 1Enclosure:Intended for indoor use primarily to provide a

degree of protection against contact with the enclosed equipment.

NEMA Type 12Enclosure:Intended for indoor use primarily to provide a

degree of protection against dust, falling dirt, and dripping non-corrosive

liquids.

NEMA Type 3 Enclosure: Intended for outdoor use primarily to provide a

degree of protection against windblown dust, rain, sleet, and external ice

formation.

NEMA 3R Enclosure: Intended for outdoor use primarily to provide a degree

of protection against, rain, sleet, and external ice formation.

NEMA 4 Enclosure: Intended for indoor or outdoor use primarily to provide

a degree of protection against windblown dust and rain, splashing water andhose directed water.

NEMA 4X Enclosure: Intended for indoor or outdoor use primarily to

provide a degree of protection against corrosion, windblown dust and rain,

splashing water and hose directed water.


13/23

13

(IV.) PRODUCTS

What is a surge protective device?

A voltage dependent component connected in parallel with the load and limits current. It

may be connected between two lines or any line and ground. It protects the electrical

system by limiting surge voltage while diverting surge current.

Series Product Line:

Advantages Disadvantages

Low clamping levels

Excellent noise attenuation

Controlled lead lengths to suppression

Potentially very large (dependent upon

protected load).

Larger units may be expensive

modules. May be difficult to service due to series

connection.

The series connected product line consists of the following:

CONTROL CONCEPTS

Islatrol

Islatrol Elite

Islatrol Plus

Islatran

Islatron

Islatrol Product Description:

High Frequency Noise Filter

Low Pass Filter

RLC Circuit/Filter

Features

Line to Neutral Filtering (Normal Mode)

Single Phase or Three Phase Applications

amp - 1200 ampere available

Attenuates (or reduces the amplitude of) noise that

occurs in a frequency range of 3 kHz to 50 MHz.


14/23

14

Islatrol Elite Product Description:

High Frequency Noise Filter with TVSS

Low Pass Filter with TVSS

RLC Circuit/Filter with TVSS

Features

Transient Suppression/Noise Filtering - All Modes

Single Phase applications only

3 - 20 ampere available

Attenuates ( or reduces the amplitude of ) noise

that occurs in the frequency range of 3kHz to 50 MHz.

45kA Transient Suppression Total

UL1449, UL 1283, CUL, CE

Islatrol Plus Product Description:




Features



2.5 - 30 ampere available

Attenuates (or reduces the amplitude) noise that occurs

in a frequency range of 3 kHz to 50 MHz.

39.9 kA Transient Suppression - Total

UL 1283, CSA

Islatran Product Description:


and Isolation Transformer


and Isolation Transformer


and Isolation Transformer Features



2.5 - 16 ampere available

Attenuates (or reduces the amplitude) noise that occurs

in a frequency range of 3 kHz to 50 MHz.

39.9 kA Transient Suppression Total


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Parallel Product Line:

Advantages Disadvantages

High transient protection

Low cost Disconnect allows unit to be taken off

Clamping levels adversely affected by

long lead lengths (installation) Filter capability not as good as series

line without interruption of service. installed devices (no inductors)

Small package

The parallel connected product line consists of the following:

CONTROL CONCEPTS

IslaGuard Series

IH (High Exposure) IM (Medium Exposure) IL (Low Exposure)

IslaGuard Product Description:

TVSS/SPD

Main/Sub Panel Mount Suppressor

Features

(IH) Islaguard High Exposure Series

- 100kA to 400kA Surge Current Capacity

- Replaceable Modules

- Alarm and Disconnect Available

- 5 year warranty

(IM) Islaguard Medium Exposure

- 100kA to 160kA Surge Current Capacity

- All mode and two mode protection

- Small footprint

- All voltage and phase configurations

- NEMA 12 metal enclosure

- Form C contact, (100-2 units ONLY), LED status indication

- 5 year warranty

(IL) Islaguard Low Exposure

-

25kA to 100kA Surge Current Capacity- All mode and two mode protection

- Small footprint

- All voltage and phase configurations

- Form C contact, LED status indication

- Sand Encapsulation

- Thermal protection

- 5 year warranty


16/23

16

(V.) SELECTION OF PRODUCTS

Islatrol:The product line is separated into six main groups.

1.

Single Phase 120 volt2. Single Phase 240 volt

3. Single Phase 480 volt

4. Three Phase120/208

5. Three Phase 277/480

6. DC (Call Application Engineer)

Each of these six main groups can be broken into sub-groups based on ampere rating (the

protected equipments current draw under normal operation).

Example: a single phase, 120-volt unit rated for a 5-amp load is an I-105

Note: The 120 volt, single phase Islatrols can be purchased as a 5 line cord/receptacle

unit or as printed circuit board mount (.25 amps) unit. We label the line cord models with

a prefix of LR (for line cord/receptacle) and add the suffix PC to the model number for

printed circuit board.

To help a customer select an Islatrol:

1. Determine Phase configuration. - Is the filter protecting a Three Phase Wye load?

Three Phase Delta configured panel? Single Phase configured panel?

2. Determine Voltage configuration- Is the filter protecting a 120/208-volt system?

480 volt system? Keep in mind if the voltage required does not match the selectionsin the catalog; always choose the higher voltage. For example: If the voltage level is

higher than 120 (say 230 V) but less than 277 select the Islatrol configured for 277

volts.

3. Determine Ampere rating of protected load: Again, if the protected load is not

specifically listed in the catalog, move to the next, higher, ampere rating available.

For example: If the load under normal operation will draw 10 amps, you would chose

a unit rated for a 15-amp load.

The model #: I-3-42001

st(I) - indicates Islatrol product line

2nd

(3)- indicates a Three Phase configuration

3rd

(4)- indicates the Islatrol voltage level (line to line) is 480

4th

(200)- indicates the Islatrol can handle a 200-amp load.


17/23

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Example 1:

Customer: "I have a 220/380 V Wye system but I dont see this voltage listed in the

catalogue. Which Islatrol do I select?

Control Concepts: "You would need an I-3-4 series, however, I need to know the ampere

rating of your protected load."Customer:"The load is 100 amps per phase."

Control Concepts: You would select an I-3-4100

Example 2:

Customer: "I want an Islatrol, single phase 120 volt with a load of 10 amps."

Control Concepts: "Would you like a hard wired unit or one with a line cord/receptacle

input and output?"

Customer: "I want a line cord/receptacle type."

Control Concepts: You would select an LRI-115.

Customer:Will this unit be too large, I see its rated for 15 amps, my load is only 10

amps?Control Concepts: This selection will be fine. Oversizing the load capability of the

Islatrol will have no affect on performance.

Islatrol Elite and Islatrol Plus

The product line is separated into two main groups.



Both of these two main groups can be broken into sub-groups based on ampere rating (theprotected equipments current draw under normal operation). The 120-volt single phase

Islatrol Plus is then offered in a hardwired or line cord/receptacle input/output

configuration.

The Islatrol Elite offers the following additional features:

1. Finger-safe terminals

2. UL1449, CUL and CE listings.

3. Form C contacts for remote indication.

4. DIN mountable enclosure.

**** Note: Both models MAX 20 Amp Continuous Load Current****


18/23

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To help a customer select Either an Islatrol Plus or Islatrol Elite:

1. Confirm Phase configuration. - Is the filter in line with a true single-phase load?

Two wires and a ground?

2. Determine Voltage - Is the filter protecting a 120-volt system? 240 volt system?Keep in mind if the voltage required does not match the selections in the catalog;



For example: If the load under normal operation will draw six amps, you would

choose a unit rated for a 7.5 amp load (Islatrol Series) or 10amp load (Islatrol Elite

Series).

4. Determine Any Special Features Desired: If DIN type mounting, additional

certification (UL1449, CUL, CE) or special terminals are desired then use Islatrol

Elite.

The Model #:LRIC+105

1st(LR) - indicates the input/output to the Islatrol plus is via line cord/receptacle

2nd

(IC+)- indicates Islatrol Plus product line.

3rd

(1)- indicates 120 volt single phase

4th

(05)- indicates the Islatrol Plus can handle a 5 amp load

Example 1:

Customer: "I have a load that draws 9 amps what product do I choose?"

Control Concepts: "I need to know the voltage and phase configuration."

Customer:The voltage is 120-volt single phase.

Control Concepts: Two wires and a ground?

Customer:Yes.

Control Concepts: Would you like a hardwired or line cord/receptacle model.

Customer: Hardwired with finger safe terminals.

Control Concepts: The Islatrol Elite model number you would select is an IE-110.


19/23

19

Islatran

The unit is separated into two main groups.



Both of these two main groups can be broken into sub-groups based on ampere rating (the

protected equipments current draw under normal operation).

The 120-volt single phase is offered in a hardwired or line cord/receptacle input/output

configuration (all models). A 2 and 6.25 amp model is available with a medical grade

receptacle (labeled as UL544). The 240-volt single phase Islatran is available in a

hardwired or line cord/receptacle input/output configuration for six and eight amp loads

only.

1. Confirm Phase configuration. - Is the filter in line with a true single-phase load?

Two wires and a ground?

2. Determine Voltage - Is the filter protecting a 120-volt system? 240 volt system?

Keep in mind if the voltage required does not match the selections in the catalog;

always choose the higher voltage. For example: If the voltage level is higher than 120

(say 230 V) but less than 240 select the Islatrol configured for 240 volts.



For example: If the load under normal operation will draw seven amps, you would chose

a unit rated for an 8-amp load.

The Model #: LRA-120

1st(LR) - indicates the input/output to the Islatran plus is via line cord/receptacle

2nd

(A)- indicates Islatran product line with standard receptacle.

3rd

(1)- indicates 120 volt single phase

4th

(20)- indicates the Islatran can handle a 16 amp load


20/23

20

IslaGuard Series

The unit is separated into three series: IH, IM, IL.

Choice of unit is determined by the following:

1. Surge current per phase requirements:2. Modes of protection required: any combination of

3. Voltage Configuration

4. Phase Configuration

To help a customer select an IslaGuard:

1. Determine Modes of Protection Requirements: Are they looking for line to line,

line to ground, line to neutral, or neutral to ground - any combination.

2. Determine Surge Current Requirements: 25kA to 400 kA

3. Determine Voltage - Is the IslaGuard installed in parallel with a 120/208 system?

240 volt system? Keep in mind the voltage requirement is very important. If the

voltages present at the panel do not match any of the selections in the catalog ,

contact Applications Engineering Dept.

4. Confirm Phase configuration. - Is the IslaGuard installed in parallel with a single-

phase panel? Split Phase? Three Phase Wye or Delta?

The Catalog Model #: IH277Y400R

1st(IH)- indicates Islaguard High Exposure

2

nd

(277Y)- indicates IslaGuard voltage/phase configuration3rd

400- indicates total protection of 400kA per phase / 200kA per mode L-N, L-G, N-G

4th

(R) - indicates Rotary Disconnect.

Example 1:

Customer: "I have a 480 volt system, what product should I select?"

Control Concepts:"Is your 480-volt system a 277/480 Three phase Wye or a 480 volt

Three Phase Delta?"

Customer: "I am not sure."

Control Concepts: Do you have 4 wires and a ground (3 phases and a neutral + gnd) or

3 wires and a ground (3 phases + gnd)?

Customer: 4 wires and a ground.Control Concepts: What modes do you want to protect?

Customer:"The specification I am looking at calls for all modes."

Control Concepts:What is your surge current requirement per phase?

Customer: I need 200,000 amps per phase.

Control Concepts: Do you need a disconnect ?

Customer:Yes.

Control Concepts: Our model number is IH277Y200R.


21/2321

(VII.) Typical Questions

Q: Is there any difference between a surge and a transient or transient overvoltage?

A: The terms are typically used to describe the very short duration increases in voltage

caused by lightning. In this context surge means the same as transient overvoltage orin its shortened form transient. However, surge is a vague term also used to describe

overvoltages up to a few seconds (swells) in duration.

Q: What is the source of electrical disturbances?

A: You can look at three main areas as a source of electrical disturbances:

1. The Utility Company- No matter where you go, commercial AC power system is

polluted with spikes, surges, and other disturbances generally called electrical

noise. Power-line noise has always been a part of the electrical utilities. Its a natural

by product of the distribution and use of electric power.If demand for power increases beyond the capacity of the utility companys generator

in one area, or if heavy industrial use overloads the power system, the corrective

action of the utility company can cause spikes and transients to appear on the power

line.

2. Lightning- Lightning strikes may not be the most common source of power-line

noise, but they are certainly the most devastating. Even when the strike is many miles

away, surges and spikes measuring thousands of volts may show up at your service.

3. Electrical Loads- Dramatic events like lightning may get all the attention when it

comes to power line disturbances, but on a day-to-day basis, much more electrical

noise is created by noisy electrical loads.

Copiers, computers, heating ventilating and air conditioning, coffee makers, power

tools, vending machines and the like throw noise back into the electrical system when

they operate.

Q:Why are todays systems so much more sensitive than they used to be?

A: There are two reasons for this:

1. Changing Power Supplies- During the last 10 years most computer manufacturers

have changed from using linear DC power supplies to switching type power supplies.

Because the switching power supplies operate by switching on and off rapidly and

drawing a lot of current during each cycle, they can generate a lot of noise.

2. Chip Complexity- The chips themselves are more complex, smaller, and more

vulnerable to noise than they used to be.


22/2322

Questions Continued:

Q: What is Let-Thru Voltage?

A: Let-Thru voltage is simply the amount of transient voltage that is allowed to pass

through to your protected load. It is the same as the clamping level. This value is typicallybased on the IEEE category B3 wave form/pulse or UL 1449 clamping level. An example

would be our let-thru voltage on an IH120Y200R is a 400-volt.

Q: What is meant by speed of response? We claim .5 ns.

A: This value is often misunderstood. The customer often believes that this value is

actually the installed response time of the surge suppresser. In reality, the speed ofresponse, is the component level speed of response, not the products. The term became

popular with manufacturers that employ Silicon Avalanche Diodes in their design -

SADs intrinsic properties give it a slight edge in response time when compared to

MOVs. However, the real worldresponse time of a unit is better represented by its

clamping capability or the UL 1449 rating.


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Product Questions

Q: How do I determine which size Islaguard to select IH, IM, or IL.

A: Unfortunately, there is no cookbook method to selecting a parallel device. Eachcustomer will be unique; therefore, you will have to ask many questions to evaluate their

need. The following is a few of the things I would ask to determine an appropriate unit:

1. Determine the Exposure Levelof the site. This includes the lightning activity in their

area, the distance from the power-generating source, the proximity to other transient

generating loads.

2. Examine Site History. Do they have a history of problems at the site?

3. The Protected Load. What are they trying to protect? Will the Interceptor be

protecting a new MRI wing with critical, expensive equipment or will it simply

protect a lighting panel

4.

The Customers Tolerance for Risk. Is the customer willing to take a chance on a

disruption in their daily activities due to equipment failure? What is the cost of their

companys downtime? Considering this cost one can easily justify the initial

investment of a suppression device. Typically, this initial cost may be less than an

hour of downtime.

5. The Customers Budget. If the end user does not have the money to invest in a

higher end suppression system, we can value engineer a solution for them.

Q: How far away from my panel can install my Islaguard?

A: As in any parallel installation of a surge protective device, you would want to get asclose as possible to the bus you are protecting. The effectiveness of a parallel device is

dramatically reduced as the lead length increases. Optimally, the best installation would

be approximately 18 inches or less from the bus.

Q: What is the difference between the Islatrol, the Islatrol Plus/ Elite, and the Islatran?

A: The Islatrol is a normal mode high frequency noise filter. The Islatrol Plus is a normal

and common mode high frequency noise filter/transient suppresser. In addition to the IC+

features the IE model is DIN mountable, has finger safe terminals and carries both UL

1449 and 1283 certification. The Islatran is a normal and common mode high frequency

noise filter/transient suppresser with isolation transformer.

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