New England AssociationOf

Fire Protection System Designers

 

Rick Dumont

Evolution of Fire Pump Controllers

with

Special Emphasis on Variable Frequency Drives

Overview of Discussion

Two different styles of controllers are used to operate fire pumps…

Electric Controllers

Diesel Controllers

Electric Motor Driven

Diesel Engine Driven

Basic Overviewof

Electric Controllers

Full Voltage

a.k.a. - Across the Line

Reduced Voltage

Full Voltage

° InexpensiveInexpensive

° Simple to buildSimple to build

° Standard 3 phase motorStandard 3 phase motor

• Smaller Enclosure sizes

Advantages: Disadvantages:

° Limits HP size due to Limits HP size due to inrush currentinrush current

° Generally not suitable Generally not suitable for generator usefor generator use

Reduced Voltage

° Primary ResistorPrimary Resistor° Wye Delta Open Wye Delta Open

TransitionTransition° Wye Delta Closed Wye Delta Closed

TransitionTransition

° Part WindingPart Winding° Auto-transformerAuto-transformer° Solid State Soft-Solid State Soft-

StarterStarter

Controller / Motor Type

° Across-the-lineAcross-the-line

° Primary ResistorPrimary Resistor

° Auto-transformerAuto-transformer

° Solid State Soft-StarterSolid State Soft-Starter

° Standard 3-phase Standard 3-phase induction motorinduction motor

Advantage?

•Most inexpensive motors

•Readily available

•3 wire connections from controller

Controller / Motor Type

° Across-the-line *Across-the-line *

° Primary Resistor *Primary Resistor *

° Auto-transformerAuto-transformer

° Solid State Soft-StarterSolid State Soft-Starter

° Standard 3-phase Standard 3-phase induction motorinduction motor

Disadvantage?

•Controller more expensive (*exception)

Controller / Motor Type

° Wye Delta Open Wye Delta Open TransitionTransition

° Wye Delta Closed Wye Delta Closed TransitionTransition

° Part WindingPart Winding

° Requires Wye/Delta Requires Wye/Delta motormotor

° DittoDitto

° Requires Part Wind Requires Part Wind motormotor

Disadvantage?

•Motor may be a long lead item

Purpose of any electric Fire Pump Controller…

…to start a motor, without jeopardizing the power source, and bring it to it’s fully rated

horsepower

Only then will a pump provide rated pressure and

flow to satisfy the design requirements.

Would it be beneficial to you as designers and installers…

…if you could limit the pressure of the system by changing the speed of the

pump?

A Variable Frequency Controller…

…can “vary” the speed of a motor to “maintain” a desired pressure in a system.

Rocket Science ?

° Domestic Water SystemsDomestic Water Systems° Chemical Feed SystemsChemical Feed Systems° HVAC SystemsHVAC Systems

Hardly !

How do they work ?

What does an AC Motor need to operate properly?

Rated Frequency + Rated Voltage = Rated Horsepower

How do they work ?

Three phase AC power

2 Components

•Frequency

•Amplitude

How do they work ?

A traditional reduced voltage controller…

…changes voltage level only

…reduces inrush current

…frequency is constant

How do they work ?

Variable Frequency Drive

Also known as…

•Variable Speed Drive

•Inverter

•VFD or VSD

How do they work ?

Variable Frequency Drive

DC Rectifiers460/3/60 Inverter0-460 vac

0-60 hz

Power Input

600 vdc

How do they work ?

Variable Frequency Drive

DC Rectifiers460/3/60 Inverter0-460 vac

0-60 hz

Power Input

600 vdc

How is pressure controlled?

Via a “Closed Loop System”

Two Components to a Closed Loop System:

How do they work ?

•Setpoint

•Feedback

Setpoint Devices…

Temperature Control Systems

How do they work ?

•Thermostat

Pressure Control Systems

•Digital Keypad

Feedback Devices…

Temperature Control Systems

How do they work ?

•Thermocouple

Pressure Control Systems

•Pressure Transducer

Setpoint Device

How do they work ?