selecting correct overload relay for motor
selecting correct overload relay for motor
(OP)
I have 3-ph,240 motor, label list amp at 4.8, when motor is idling am on each leg is 2.3, 2.0,2.3; when cycle runs amp rises to 2.5,2.3,2.5. on start up jumps to somewhere close to 5 but happens so fast cant tell. I have three allen bradley relays, 2500 (20-25amp) 1500 (10-20amp) and 1000 (6.5-10amp) one of them came from here but Which one, or is none appropriate. How would I determine. One last thing, how would i know if I have delta or wye configuration ..just curious)






RE: selecting correct overload relay for motor
For large or oversized motors running well below rated current, some prefer to set the OL to 125% of the normal load current.
To determine type of connecitons, it depends on what is accecible (leads). If all six leads are brought then it is easy to determine. If it has six terminals (2 rows and 3 columns) and all shorting links are veritcal then it becomes delta connected. If one of the rows (normally bottom) is shorted, if becomes star connceted.
If only 3 leads are brought out you may have to determine by inspection.
I am sure you will see additional posts form experts in motors.
RE: selecting correct overload relay for motor
2.5+2.3+2.5 = 7.3
RE: selecting correct overload relay for motor
You set at 1.25*4.8=6A.
Also look at Thread238-96044
RE: selecting correct overload relay for motor
I dont think any of the relays you have are suitable for this installation except the 6.5A one is marginal. I would not use it.
RE: selecting correct overload relay for motor
"Venditori de oleum-vipera non vigere excordis populi"
RE: selecting correct overload relay for motor
RE: selecting correct overload relay for motor
RE: selecting correct overload relay for motor