3ph star delta starter motor drawing high amps

[Simon-0116]

Star delta starter / motor problem.
Starter starts runs as should on bench with no motor connected. Getting 230v to e on all 6 uvw 1s and uvw2. 415 u1 to v2 etc etc. But nothing 1 to 2s. As expected.
When motor connected up. (Single speed) it takes 3a in start on all . Drops into run fine but is taking 38a on all.
After 5 seconds it trips breaker.


Any ideas were to start. As both out of stores as spares and checking they work but now stumped

 

[Cadgey123]

Does the motor have a load connected to it?
Also check insulation resistance tests of the windings and continuity of windings.

 

[westward10]

Is this a recent problem on an existing motor or an issue on a new install.
PS. No such thing as a star/delta motor.

 

[elsparko]

can you offload it onto a coworker? take time off work and hope its fixed when you get back?

 

[westward10]

You need to clarify your opening post it is somewhat confusing.

 

[elsparko]

You need to clarify your opening post it is somewhat confusing.

 

[Simon-0116]

Does the motor have a load connected to it?
Also check insulation resistance tests of the windings and continuity of windings.

No load just on bench. Insulation is acceptable. In runs fine in start so presume windings are fine.

 

[Simon-0116]

Is this a recent problem on an existing motor or an issue on a new install.
PS. No such thing as a star/delta motor.

Never said was a star delta motor. It's just 2 items out of stores we were checking that are ok.

 

[elsparko]

how long has it been in stores? corrosion ? have you taken it apart or blown pressurised air through it?

 

[ruston]

Was the timer previously set for that motor?

 

[Simon-0116]

how long has it been in stores? corrosion ? have you taken it apart or blown pressurised air through it?

No not blown it out but it runs fine when connected to dol started with links in motor 3 wire.
It seems like losing a phase / low voltage high current???

 

[Cadgey123]

Post a picture of the motor and the nameplate.
And if you can the gubbins inside the starter

 

[elsparko]

could be a few things, im no expert on motorwindings but when they lose balance tends to be when things go pete tong, was there a reason it was stored away no longer used or was it working last time it was tested?

 

[Andy-1960]

I would double check the wiring as the motor could be single phasing when it goes into delta ( same phase across both end of the one winding)

 

[marconi]

 

[Pete999]

Star delta starter / motor problem.
Starter starts runs as should on bench with no motor connected. Getting 230v to e on all 6 uvw 1s and uvw2. 415 u1 to v2 etc etc. But nothing 1 to 2s. As expected.
When motor connected up. (Single speed) it takes 3a in start on all . Drops into run fine but is taking 38a on all.
After 5 seconds it trips breaker.
When you say the Starter runs OK with no Motor connected, are you saying the Starter operates as it should? and what do you mean by single speed?
If the Motor is starting, and connecting the Motor's winding in a Star configuration, but trips when it changes into a delta mode, then it sounds like you have either a faulty Motor, of you have it wired up incorrectly.

Any ideas were to start. As both out of stores as spares and checking they work but now stumped

 

[Pete999]

Star delta starter / motor problem.
Starter starts runs as should on bench with no motor connected. Getting 230v to e on all 6 uvw 1s and uvw2. 415 u1 to v2 etc etc. But nothing 1 to 2s. As expected.
When motor connected up. (Single speed) it takes 3a in start on all . Drops into run fine but is taking 38a on all.
After 5 seconds it trips breaker.

Any ideas were to start. As both out of stores as spares and checking they work but now stumped

 

[Rocboni]

No not blown it out but it runs fine when connected to dol started with links in motor 3 wire.
It seems like losing a phase / low voltage high current???

Why do you need to start it via star delta if you are able to start it DOL, how big is the motor and are the windings rated 415/690 or there abouts?

How are you connecting the links when starting DOL I presume star as you say it starts fine when connected up to the star delta.

My bets on delta contactor in starter... although I can't understand from your original post if you've checked this?

 

[Pete999]

Why do you need to start it via star delta if you are able to start it DOL, how big is the motor and are the windings rated 415/690 or there abouts?

How are you connecting the links when starting DOL I presume star as you say it starts fine when connected up to the star delta.

My bets on delta contactor in starter... although I can't understand from your original post if you've checked this?

https://www.quora.com/Why-is-star-delta-starter-preferred-with-an-induction-motor

 

[Rocboni]

https://www.quora.com/Why-is-star-delta-starter-preferred-with-an-induction-motor

I understand this Pete but a motor that only draws 3A on start up doesn't need to be connected to a star delta starter to reduce starting current does it? without seeing the rating plate it's obviously small motor