magnetic sep comments

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EXCEL CONSULTING ENGINEERS PVT. LTD.No. 72, Kasi Estates, Ashok Nagar, Chennai – 600 083. Tel : 474 5586; Tele Fax : 474 4000

E mail : [email protected]

Ref. XL/FIL/989/742 1st February 2001

Fenner (India) Limited.,

82, Peters Road,Chennai – 600 014

Kind Attn : Mr. Subbaraj / Mr. ManikandanDGM – Engg.

Dear Sirs,

Sub : Detail Engineering for Bagasse Handling System for 24MW CPP – GodavariSugar Mills Ltd. – Comments on Vendor Drawings of Magnetic Separator System.

Please find enclosed our comments on the vendor drawings of Magnetic Separator system receivedby us on 24.01.2001. Please find our draft letter to the vendor along with our detailed comments.Please forward the same for necessary action. Please ensure also to obtain ‘filled in page no. 3and 4 of Technical Specification’ ( Data Sheet) for our review and records.

Thanking you and assuring you of our best services at all times,

Very truly yours,for EXCEL CONSULTING ENGINEERS PVT. LTD.,-sd-

S RENGARAJAN.

Director Encl. As above

mailto:[email protected]

mailto:[email protected]



DRAFT LETTER

M/s. Magnet Industries (CAL) Pvt. Ltd.,

Sirs,

We are in receipt of the following drawings:

DRAWING NO. DRAWINGDATE

TITLE

MI/F-GSL1/704 18.01.2001 GA Drawing of Overband Crossbelt Magnetic Separator For 1400 mm conv. belt.

MI/F-GSL3/721 18.01.2001 GA Drawing of Power/Control CKT. for Overband

crossbelt Electro Magnet separator.

MI/F-GSL/720 18.01.2001 GA Drawing of Control Panel for overband crossbeltElectro Magnet Separator.

MI/F-GSL4/703 18.01.2001 BOM of Control Panel for overband crossbelt ElectroMagnet Separator.

Our comments on the ‘electricals’ included in the above drawings are as under :

1.0 Drawing No.GSL1/ 704:

1.1 Furnish details of magnet i.e. its Metallurgical Constitution and the Indian Standardsthat it conforms to, etc., in line with Clause 2 of Technical Specification.

1.2 Furnish detailed drawings on terminal blocks, earthing arrangement provided insidethe terminal box and also bring out the details of how you are ensuring water tightness,especially to the place where the leads are brought out of the terminal box. (It may be water tightsealed gland or any other suitable arrangement).

1.3 Please confirm power requirement for magnet (to verify adequacy of 4kVA transformer).

2.0 Drawing No.GSL3 / 721:

2.1 You have included remote system (PLC system) STOP interlock common for both local &remote. The local mode operation shall be without any interlock. As such, please provideseparate circuitry for remote system START contact multiplication, the converse of whichcan be used for stopping in the contactor circuit, in the remote mode. Further, by theremote system START terminals 3, 4 indicated by you, we presume , you mean ‘ metaldetector’ (placed preceding MS ).If so, please incorporate so. In addition, the following shallbe incorporated in the control schematic diagram :a. Furnish control mode / non control mode through a selector switch which shall be

lockable (which are normally provided to by-pass MS when not needed, when onmaintenance).

b. As per specification, the magnet has to be switched ON, switched OFF throughcontactor on the secondary side of the transformer, the NC contacts of which has tobe wired to discharge resistor. None of these specified items are found in thescheme.



c. Provide also the disconnect switch on the main incoming side and also each of thefeeders, namely, magnet and motor. The power circuit should not be isolated bypulling of fuses.

d. Also please take care of the following comments also while revising the drawings.

2.2 Provide control fuse in the RYB bus supply indicating lamp circuit.

2.3 Mark in the motor outgoing circuit power terminal blocks that is to be used for connecting theoutgoing cable to motor.

2.4 Provide one potential free NO contact to external terminal block which gives MS ready feedback to PLC.

2.5 What about fast acting semi-conductor fuse for the diode circuit. We find that you have onlyprovided F12, F13 which is to protect the load side.

2.6 What about zero speed switch specified to detect any overload on the motor driving the belt of magnetic separator. As per clause no.2 of specification chain / belt drives shall not beaccepted.

2.7 Also provide one potential free NO contact wired to external terminal block that would beactivated when magnet is on.

2.8 Provide MS-fault signal through the potential free NO contact wired to external terminal block.(For PLC input). This fault signal shall be activated for any kind of fault in the MS system whichindicates that the magnetic separator is not able to function satisfactorily. (motor tripped onover load, zero speed switch activated, etc.).

3.0 Drawing No. GSL / 720 :

3.1 Panel shall be made up of CRCA of minimum 2 mm. thick and IP 54. Please indicate this

as a note in the drawing.3.2 From the GA drawings that you have submitted, it seems that the panel is cramped

especially the rectifier compartment which also accomodates 4 kVA transformer TR1. Whatabout the accessibility for the transformer primary and secondary terminals. From whichside are they accessible? Is it only from the back? We also find that fuse F1 to F6, F12,F13 are placed very near the panel bottom, there by causing inconvenience to remove andput them back. Please consider shifting them to a comfortable height.

3.3 Panel height may be increased (considering point 3.2 above) as it will be mounted insideswitchgear room along with MCC, etc (which are about 2300 mm high). Please furnishdrawings indicating the fixing arrangement namely number of holes / slots, position anddiameter. Also indicate removable gland plate at the bottom.

3.4 The terminal block is also placed very near the panel bottom. Please ensure to keep aminimum of 300 mm clearance between the bottom most terminal block and the removablegland plate. Also furnish a detailed drawing showing the power terminal block arrangementwith terminal numbers clearly marked, and the arrangement what you are proving for extending the incoming supply to the bus bar, and also extending the outgoing supply to the5 HP motor.

3.5. The tap changing switch S3 also seems to be placed at a lower elevation. Please shift it to acomfortable operating height. With this arrangement please ensure that all operating deviceslike switches, handles, etc., shall be at a comfortable operating height of 1.6 meter from thefloor level and all indicating instruments are at a convenient height to ensure proper eyecontact).

3.6 Provide overload relay reset push button on the door. It shall be possible to reset the

overload relay of the motor without opening the door.3.7 Provide overload relay Trip indication lamp, Magnet operated lamp, MS fault lamp and MS

ready lamp on the door.

4.0 DRAWING NO.: GSL 4 / 703.



4.1 For incoming power supply and outgoing magnet feeder and for 5 HP motor provide fuseswitch unit as mentioned elsewhere. Hence, please modify your BOM accordingly. Also,include contactor for controlling magnet, its discharge resistance, etc.

4.2. Include the 5 HP motor overload relay and the reset arrangement in the BOQ. Indicateoverload relay range and mention that it is with built in single phasing preventor.

4.3. The PIV of diodes should not be less than 1560 volts as mentioned in our clause no.2 of Technical Specification. Hence, please modify the BOQ accordingly.

4.4 Please clarify regarding scope and details of interconnecting power and control cablesfor MS.

Apart from taking care of all the above comments for revising the drawings, please furnishthe filled up data sheet (page no.3 and 4 of Technical Specification) included along with theTender Specification.

Thanking you,

Yours faithfully,for FENNER (INDIA) LIMITED,

magnetic sep comments

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