3ph motor on inverter

[maxsib]

Hi Guys,
Thanks for the add, got a reasonable understanding but motors ant my thing.

Trying to run a 3kw 3ph motor on a Alan Bradley Inverter that I Have had for a few years.

It isn't happening on load so 3000/240 is 12.5A this total so 4A per phase?


So the AB is rated at 230v 12A is 2760 or 2.7kw so pretty close.

So it should work but stalls freq is set at 50Hz. 134a plug off the ring.


Am I missing something?


Cheers


Max

 

[Darkwood]

I'm going to establish a few things here,
-The drive is 1ph to 3ph
-You meant to say 13amp not 134amp plug top

You need to look at the technical spec listed in the manual, the drive itself will be plated for its input current and well as listed in the manual, they are also normally reference to suitable OCPD's to protect them too, my first concern would be designed earth leakage and fault masking, the socket if up to regulations will be rcd protected and a 3kw motor drive is likely to give nuisance tripping, also there could be noise coming back from the drive that mask the rcd device which can block it from operating correctly... you will need to run the motor and do some rcd's meter tests to ensure it still operates correctly (if it does not nuisance trip).

My second concern is 3kw motors are approx 6amps at 400v per phase and approx 12amps at 230v per phase (ball park), a drive for this I suspect would be well above a standard plug top rating as you may be looking at 25amp to 30amp input.

 

[maxsib]

I'm going to establish a few things here,
-The drive is 1ph to 3ph
-You meant to say 13amp not 134amp plug top

You need to look at the technical spec listed in the manual, the drive itself will be plated for its input current and well as listed in the manual, they are also normally reference to suitable OCPD's to protect them too, my first concern would be designed earth leakage and fault masking, the socket if up to regulations will be rcd protected and a 3kw motor drive is likely to give nuisance tripping, also there could be noise coming back from the drive that mask the rcd device which can block it from operating correctly... you will need to run the motor and do some rcd's meter tests to ensure it still operates correctly (if it does not nuisance trip).

My second concern is 3kw motors are approx 6amps at 400v per phase and over 12amps at 230v per phase (ball park), a drive for this I suspect would be well above a standard plug top rating as you may be looking at 25amp to 30amp input.

yep 1to 3ph and 13A
Inverter rated at 25A input Set to 15A which is max in parameters

I can run 40 a radial if needed just trying to see if it will work albeit jerry rigged. Volt drop minimal?

Its holding on a 13A fuse

Need to see how motor is configured guess it would be better in Delta, there is no starter as such just a straight forward contractor which has been changed to a 240v running across 2 phases = 230v as the original was 415 and chatering unless it was pushed in as voltage to low to pull it.


Cheers


Max

 

[Julie.]

There's a whole host of possibilities here, assuming you do have a single phase to three phase inverter, the most common issue is that of voltage, a typical 1ph - 3ph inverter outputs 230V phase-phase rather than the normal 400V.

As such you have to use a motor that is wound for duel voltage - it connects in star for use on a 400V system and delta for a 230V system - this is not the same as a 400V motor started as star-delta!

We would need better details of the actual motor and drive to be sure.

The other issue is that the inverter is never 100% efficient, so under load although the 4hp motor translated to a single phase supply is 13A in practice it would be more than this.

Under no load it should be ok, but you could have inappropriate settings limiting the motor start - there are often lots of options with the inverter and it is easy to configure it in such a way that things don't work properly

 

[Julie.]

yep 1to 3ph and 13A
Inverter rated at 25A input Set to 15A which is max in parameters

I can run 40 a radial if needed just trying to see if it will work albeit jerry rigged. Volt drop minimal?

Its holding on a 13A fuse

Need to see how motor is configured guess it would be better in Delta, there is no starter as such just a straight forward contractor which has been changed to a 240v running across 2 phases = 230v as the original was 415 and chatering unless it was pushed in as voltage to low to pull it.


Cheers


Max

OK, this crossed in the posting, but we would need to see the rating label/wiring diagram of the motor.

 

[Darkwood]

yep 1to 3ph and 13A
Inverter rated at 25A input Set to 15A which is max in parameters

The info you give is confusing, what is set to max 15amps, you cannot set input demand on a drive only the output which is set by following the motor rated current, I can only assume you have set the motor rated output here to 15amps per phase which will likely be over rated for the motor.
I think you are delving into a project here with next to no understanding at all as you have already stated, not only are you confusing the basics of the ratings of the drive and motor, you also are getting confused by the parameter settings and what they mean.
With all respect you should bring someone in with experience on these things as it is difficult to do over a forum when you are clearly getting confused over the info you provide.
If you can post the info of the motor plate or better still a pic.

 

[maxsib]

There's a whole host of possibilities here, assuming you do have a single phase to three phase inverter, the most common issue is that of voltage, a typical 1ph - 3ph inverter outputs 230V phase-phase rather than the normal 400V.

As such you have to use a motor that is wound for duel voltage - it connects in star for use on a 400V system and delta for a 230V system - this is not the same as a 400V motor started as star-delta!

We would need better details of the actual motor and drive to be sure.

The other issue is that the inverter is never 100% efficient, so under load although the 4hp motor translated to a single phase supply is 13A in practice it would be more than this.

Under no load it should be ok, but you could have inappropriate settings limiting the motor start - there are often lots of options with the inverter and it is easy to configure it in such a way that things don't work properly

Hi,

Thanks for your help!

By dual voltage do you mean the jumpers in connection box on the motor? I think its in star as the jumpers run across the connections rather than in inline need to look.

Drive is a an AB power flex 40 22b-A012N114 rated at 25A input.


Motor runs fine no load but stalls when load comes on.


Rgs



Max

 

[Julie.]

Hi,

Thanks for your help!

By dual voltage do you mean the jumpers in connection box on the motor? I think its in star as the jumpers run across the connections rather than in inline need to look.

Drive is a an AB power flex 40 22b-A012N114 rated at 25A input.


Motor runs fine no load but stalls when load comes on.


Rgs



Max

Yes, but you need to check the motor rating plate, not all motors are suitable for operation at 230V.

 

[maxsib]

Yes, but you need to check the motor rating plate, not all motors are suitable for operation at 230V.

Hi


can't easily get to the motor plate without removing motor and its 8' up in the air......but changed I think to delta( uncommoned 3 ends of the windings) and it works so perhaps its ok!?

Only going to run 40 seconds at a go and not that often.

thanks for your input, great forum, I know I've got a question regarding and overhead supply and surge protection but that's further down the line.

Thanks again


Max