CLASSES OF DUTY
The following are the duty types:
A duty type is designated by mean of the abbreviation given below. For the duty type S2 the abbreviation is followed an indication if the duration of the duty. For duty type S3 and S6 the abbreviations are followed by an indication of the cyclic duration factor.
Examples: S2 60 minutes S3 25 percent S6 40 percent
For the duty types S4 and S5 the abbreviation are followed by the indication of the cyclic duration factor, the number of duty cycles per hour (c/h) and the factor of inertia (FI)
Example: S4 25 percent 120 Starts / hr Load factor =2 (Load Factor = Load Inertia / Motor Inertia) For the duty type S7 the abbreviation is followed by the number of cycles per hour and the factor of inertia.
Example: S7 500 Starts / hr Load Factor = 2
For the duty type S8 and S9 the abbreviation is followed by the indication of the number of duty cycles per hour and the factor inertia
together with the load. In addition, the cyclic duration factor should be indicated for each speed.
Examples: S8 or S9 30 Starts / hour Load Factor = 3
S2/S3 RATED MOTOR OUTPUTS
Standard motors can be used for S2 and S3 duties with increased outputs. However, the starting torque and pullout torque as percentage of full load torque would be reduced. The ratings indicated in the table are with minimum 200% pull out torque.
TEMPERATURE RISE AND INSULATION GLASS
Normally motors are insulated to Class “F” with a temperature rise restricted to Class “B”. Class “H” insulation can be produced if required. All the motor winding with VPI treatments
Theratings and performance values are specified at 40ºC ambient temperature and below 1000 meter altitude. However the same motor can be used with higher ambient temperature and altitude but has to be derated as specified in adjoining tables.
Normally motors are protected against over current by overload relays, fuses or MCBs. For thermal protection, motors can be supplied with thermister or thermal switch. For condensing environments, motors with space heaters can be supplied as well. The table below is a general guide line for selection of fuse ratings.
Motors with six terminals have to be connected in accordance with supply conditions. Verify the connection instruction before putting the motor in operation. With different connections of the motor, it is possible to use the same motor at different voltage supplies (Dual voltage motor) Star Connection – On Six termination plate, connect U2, V2 and W2 with link supplied along with the motor and connect three phase supply wires to U1, V1 and W1 to connect the motor in star connection. Delta Connection – On a Six Termination plate, connect V1-U2, U1-W2 and W1-V2 with the link supplied along with the motor and connect three phase supply wires to U1, V1 and W1 to connect end of one phase to beginning of next phase.
While changing the connections, ensure that the rated Voltage is maintained on the supply to brake, rectifier or any other type of equipment that is directly connected to the motor termination.
The standard test programmes are divided into four parts: routine tests type tests, optional tests and special tests. The routine test program is done to every machine and it is included in price of the machine. Type test is performed in addition to routine tests normally to one of the machines of a series of similar machine or by a request of the customer. Optional tests and special test are additional type tests subject to mutual agreement between purchaser and the manufacturer.
CONTENTS OF TEST PROGRAMMES:
1. Insulation resistance test
2. Measurement of resistance of the stator
3. Locked rotor test
4. No load test
5. Reduced voltage running test
6. High voltage test
1. Vibrational severity test
2. Sound level measurement
3. Degree of protection test
4. Temp. rise test at limiting values of voltage & frequency variation
5. Over speed test
6. Test on insulation system
2. Measurement of resistance of stator
3. Locked rotor test
4. Temperature rise test
5. Full load test
6. No load test at rated voltage
7. Reduced voltage running test
8. Momentary overload test
9. Insulation resistance test
10. High voltage test
SPECIAL CUSTOMIZED DESIGNS