Wye / Delta motors

[Strahan]

Need some help. I have a motor that has a namplate written in Chinese. I translated to english. 240V 3phase (single voltage) 6 lead motor. Connection diagram only shows a wye connection for the 6 leads. Nameplate current is 1.8amps. This motor is a pump motor for a CIP skid. Unfotunately this motor has burned up after running only a short time. Upon putting another motor on same specs I ran the motor and checked current with no load except the impeller. Readings were already at 1.8 amps without pumping any water. I feel this motor is undersized or there is a mechanical issue with the connection of the impeller. Manufacturer says everything is sized right. I even had a suggestion of connection it in delta. Nameplate clearly shows a wye config and not a delta besides I don't know what this will prove. Any help or suggestions?

 

[ActionDave]

Need some help. I have a motor that has a namplate written in Chinese. I translated to english.

How did you do this? Google Translate?

240V 3phase (single voltage) 6 lead motor. Connection diagram only shows a wye connection for the 6 leads.

What information is on the nameplate? It depends on the motor but it is common to use Wye/Star for high voltage and Delta for low voltage connections on IEC motors.

Nameplate current is 1.8amps. This motor is a pump motor for a CIP skid. Unfotunately this motor has burned up after running only a short time.

No heaters on the motor starter?

Upon putting another motor on same specs I ran the motor and checked current with no load except the impeller. Readings were already at 1.8 amps without pumping any water.

I agree you would expect in to pull less than nameplate amps with no load but it may not. I would check it while it's pumping and see if it goes over FLA.

I feel this motor is undersized or there is a mechanical issue with the connection of the impeller. Manufacturer says everything is sized right. I even had a suggestion of connection it in delta. Nameplate clearly shows a wye config and not a delta besides I don't know what this will prove. Any help or suggestions?

You already burnt up one motor hooking it up Star. Try it in Delta and see what your amp meter says.

 

[Strahan]

How did you do this? Google Translate?

There is an app for that

What information is on the nameplate? It depends on the motor but it is common to use Wye/Star for high voltage and Delta for low voltage connections on IEC motors.

240V .75KW 1.8amps. Only shows a wye connection. No delta connection shown so I'm figuring since it is not on nameplate I shouldn't use it.

No heaters on the motor starter?

Yeah also from over seas did not drop starter.

I agree you would expect in to pull less than nameplate amps with no load but it may not. I would check it while it's pumping and see if it goes over FLA.

Need to do this yet.
You already burnt up one motor hooking it up Star. Try it in Delta and see what your amp meter says.

Tried this motor ran at about 4.4amps. Since it's not on nameplate I figure windings are not rated for this.

 

[Strahan]

If the namplate does not show a delta connection than I assume the motor is not rated for it???? Thoughts

 

[ActionDave]

Tried this motor ran at about 4.4amps. Since it's not on nameplate I figure windings are not rated for this.

No load amps right? That's too low.

Hook it up in Star, run it under load, check amps, throttle down the valve on the output of the pump if you have to to lower the amps and make sure you tell your next higher up something is #/%**. It's guerrilla warrior advice I know. That's where I live a lot.

 

[Strahan]

No load amps right? That's too low.

Hook it up in Star, run it under load, check amps, throttle down the valve on the output of the pump if you have to to lower the amps and make sure you tell your next higher up something is #/%**. It's guerrilla warrior advice I know. That's where I live a lot.

I will give this a shot. Not sure how this will turn out. Without pumping anything I'm already at full load. I hate dealing with stuff I need to translate first.

 

[kwired]

Might want to verify that you have a single speed and/or single voltage motor.

Some six lead motors are two speed motors.

If the six lead are indeed just the ends of three coils - connecting them in wye and applying 240 volts puts about 138 volts across each coil. Connecting them in delta puts 240 volts across each coil. Applying 208 volts would put 120 volts across each coil in a wye configuration.

Also maybe check continuity between leads - it may give you some clues as to how this motor is wound. If it is simply six leads connected to three coils each lead should only have continuity to one other lead. If any one lead has continuity to more then one other lead - you probably don't have what you think you have, or something is damaged or not right. Also make sure you don't have one coil connected in the wrong sequence, as it will put wrong magnetic polarity on that coil and will inhibit output torque, but will increase input current. (it will be opposing the other two coils instead of working with them).

 

[Strahan]

Might want to verify that you have a single speed and/or single voltage motor.

Some six lead motors are two speed motors.

If the six lead are indeed just the ends of three coils - connecting them in wye and applying 240 volts puts about 138 volts across each coil. Connecting them in delta puts 240 volts across each coil. Applying 208 volts would put 120 volts across each coil in a wye configuration.

Also maybe check continuity between leads - it may give you some clues as to how this motor is wound. If it is simply six leads connected to three coils each lead should only have continuity to one other lead. If any one lead has continuity to more then one other lead - you probably don't have what you think you have, or something is damaged or not right. Also make sure you don't have one coil connected in the wrong sequence, as it will put wrong magnetic polarity on that coil and will inhibit output torque, but will increase input current. (it will be opposing the other two coils instead of working with them).

Verified continuity today and it is a 6 lead 3 coil motor. Continuity checked out ok each lead only has continuity to one other. I'm not sure what you mean about the polarity? How would I determine this?

 

[ActionDave]

Verified continuity today and it is a 6 lead 3 coil motor. Continuity checked out ok each lead only has continuity to one other. I'm not sure what you mean about the polarity? How would I determine this?

If one of the coils were miswired at the factory or made your connections wrong in the peckerhead you would have a "bucking coil". It can happen but not very often.

 

[kwired]

Verified continuity today and it is a 6 lead 3 coil motor. Continuity checked out ok each lead only has continuity to one other. I'm not sure what you mean about the polarity? How would I determine this?

There may be a science to determine, but you only have three coils to pick from - how about trying to reverse polarity one at a time and see what results you get? Could simply be an error in marking motor leads when it was manufactured results in one coil having wrong polarity.