Detailed Product Description
Computer program for the benefit of Motor Re-winders.
The performance characteristics of ageing motors deteriorate over a period, and when power consumption is heavy, they are normally scrapped. Such motors are normally rewound and put to operation once again. Some of the motors of past design are quite sturdy, and except for the rotor wear and damage during operation, the other parts of motor do not undergo so much of damage, particularly the stator frame, terminal box and end covers etc. These motors can be successfully retrofitted to the extent possible, with in the frame size and design. For rewinding and for maintaining the correct air gap, it is necessary the critical dimensions of the motor are maintained during repeat assemblies, as per the frame size, motor speed, type of winding and power rating. Unfortunately for these motors of old design, such design/performance data is either lost or not legible. Under the circumstance, correct retrofitting becomes an impossible task.
A computer program was developed to generate critical dimensional and performance data of squirrel cage / wire wound motor, with minimum inputs from the motor. The name plate details are the minimum that is expected to be fed to the program.
The computer program output gives sufficient dimensional details of the motor, for maintenance of the correct air gap and also details required for rewinding. Details like the pole pitch, slot width, area of the groove etc., enable correct rewinding of the motor with optimum copper wire dimensions. Sample input and output data of the computer program, is enclosed below. The computer program is very much useful for motor rewinders and for those involved in quality assurance studies related to electric motors.
Guidelines for using the program
The programme is based on standard design procedure adapted for squirrel cage and wire wound induction motors. The efficiency and power factor of the machine are arrived at using a polynomial fitted for the purpose. This is a curve fitting exercise using different data available from leading manufacturers and established design data. IF.ELSE END IF logic is used for the above.
The program is supplied in the executable format ZTM.EXE, and does not need any support other than input data to execute the program. Use the standard EDIT command in DOS mode of operation, to edit the input and output files IPE and OPE. Enter the 9 digit key number supplied with the pack, as sequential input data at serial number 1 in input file IPE. Then on Enter Sequential input data at Serial numbers 2 to 7, as shown in input file IPE. After saving the input file, execute the program ZTM.EXE. The output file OPE; will be automatically written in the floppy disc at A drive. If the program does not run at all, check for the correctness of the nine digit key number. If there are overflow errors and run time errors, check for major deviations in input data like the stator bore diameter which should not be less than 0.100 metres and not greater than 0.500 meters. Same way Insulation class can be only six classes. HP should not be more than 250 . The program is meant for single client use and as such will not work if copied on to another application. Each client has a separate key number for security purpose. Major output performance parameters as given in serial number 1 to 66 in the output file OPE, can be compared with motor manufacturers recommendations, and discrepancies if any, may please be brought to our notice to enable us to modify the program accordingly.
SAMPLE SEQUENTIAL INPUT DATA IPE FOR PROGRAM EXECUTION
01, xxxxxxxxx Nine digit number key given. to clients
02, 15 Motor Horse power as indicated in name
03, 1500 Revolutions per minute of shaft rotation.
04, 0.075 Stator bore diameter in meters.
05, 2 Type of rotor arrangement in motors.1 for
Slip ring, and 2 for Squirrel cage induction
06, 2 Insulation class1 to 6, designates class A
to F Insulation.
07,200 Line voltage, 230 for single phase and 415
for three phase.