Star Delta motor into DOL starter?

[TomS]

Hello everyone. I have a new star delta pump (7 core flying lead) that has to be made off into a DOL single contactor starter. Is this possible and does anyone know how?

 

[Deleted member 72666]

Out of interest, what size is the pump motor?

 

[TomS]

Out of interest, what size is the pump motor?

4kw mate. Only a baby.

 

[Deleted member 72666]

Refer to the manufacturers instructions re: connecting in star or delta, and with a multimeter set to resistance ascertain the winding pairs e.g. U1/U2, V1/V2 and W1/W2, (the earth should be the easiest to determine) If to be connected in star formation then connect U2, V2 and W2 together and use the remaining for the supply L1/U1, L2/V1 and L3/W1.

 

[TomS]

Refer to the manufacturers instructions re: connecting in star or delta, and with a multimeter set to resistance ascertain the winding pairs e.g. U1/U2, V1/V2 and W1/W2, (the earth should be the easiest to determine) If to be connected in star formation then connect U2, V2 and W2 together and use the remaining for the supply L1/U1, L2/V1 and L3/W1.

Nice one. Makes sense re the star connection. What If its to be in delta?

 

[Deleted member 72666]

In delta you would still need to find the start and finish of the windings as stated previously but connect U1/W2 together, U2/V1 together and V2/W1 togther with L1, L2 and L3 respectively. Be mindful of machine rotation for both cases.

 

[TomS]

In delta you would still need to find the start and finish of the windings as stated previously but connect U1/W2 together, U2/V1 together and V2/W1 togther with L1, L2 and L3 respectively. Be mindful of machine rotation for both cases.

Brilliant. If ever in Kent I owe ya a beer! Cheers mate.

 

[Deleted member 72666]

Oh, and welcome to the forum!

 

[TomS]

Oh, and welcome to the forum!

Haha cheers. Sorry just one more thought. If the motor has tails for star delta connection and I'm wiring it DOL, how would I decide if it's star DOL or delta DOL? I mean it's 4kw so I'd assume delta but will the motor plate say?

 

[westward10]

Assuming it is rated 400V when connected in delta then it will run at reduced torque if connected in star.

 

[TomS]

Assuming it is rated 400V when connected in delta then it will run at reduced torque if connected in star.

Daft question but why would anyone want to run it in Star then? Why would you choose to run it at a reduced torque?

 

[westward10]

I suspect the motor should be run in delta, assuming it is rated at 400V in delta then to run it in star and achieve the same torque you would need a 690V supply. If the motor has a cooling fan to draw air across the casing fins then it may not be cooled sufficiently if connected in star using 400V which could result in winding burn out. There could be many reasons why it has a 7 core flying lead from it, assuming one is the cpc.

 

[TomS]

I suspect the motor should be run in delta, assuming it is rated at 400V in delta then to run it in star and achieve the same torque you would need a 690V supply. If the motor has a cooling fan to draw air across the casing fins then it may not be cooled sufficiently if connected in star using 400V which could result in winding burn out. There could be many reasons why it has a 7 core flying lead from it, assuming one is the cpc.

That's ace mate thank you.

 

[Pete999]

Hello everyone. I have a new star delta pump (7 core flying lead) that has to be made off into a DOL single contactor starter. Is this possible and does anyone know how?

No such thing as a Star Delta Motor Tom, it's how it is connected that determines wether it is S/D, can you post a picture of the wiring in the starter?

 

[KennyKen]

Look at the Decal's on the motor plate. The information ie rated current. Winding configuration and torque ratio will be listed for both star and delta.