440/480V 12-Lead Motor
- Thread starter mull982
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LawnGuyLandSparky
Senior Member
Wire it either wye or delta. Some areas call 277v 265v. It's just a matter of how detailed you want to be with your math.
I'm not sure I follow what you are saying here. It can be wye or delta?
What about the series vs parallel windings with the 12 lead?
Are the leads not labled T1 thruT12. , and is there not a terminal connection diagram on the motor sometimes the name plate??
Are you certain that the motor is not 480/208 or 440/220???
or is it possible you have a multi speed motor or delta start- wye run??
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Yes there are numbers but no connection diagram
mcclary's electrical
Senior Member
- Location
- VA
If you're starting this accross the line, it needs to be Delta.
Here is a good place to start
but I still have concerns regarding the voltage ratings
http://apps.motorboss.com/connections/908000.pdf
but I still have concerns regarding the voltage ratings
http://apps.motorboss.com/connections/908000.pdf
Motor nameplate says "wye delta" "440/480" "blank/52A"
Motor is started from vfd
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
If I had to guess, I would figure that there is a typo on the name plate, and that it should say 240/480. The nameplate voltages on motors are usually lower than the nominal supply voltages, eg. 230/460 for a 240/480 supply, so this is still a little odd.
Guessing further, the motor uses standard NEMA numbering, that the delta connection is what is normally used for running at nominal voltage, and the wye connection is used for starting. See http://www.malloyelectric.com/pages/tech/connections.html
Having said this, I would want to double check with measurements. You can easily check continuity to see if that matches the NEMA standard, but this won't tell you polarity of the coils. There are specialized analysis tools that can be used to measure polarity, but if this is not something that you are going to do frequently I doubt that it is worth the investment. Instead I would connect the motor in my best guess as to the proper connection, and then power it at reduced voltage and measure currents on the various leads.
-Jon
Guessing further, the motor uses standard NEMA numbering, that the delta connection is what is normally used for running at nominal voltage, and the wye connection is used for starting. See http://www.malloyelectric.com/pages/tech/connections.html
Having said this, I would want to double check with measurements. You can easily check continuity to see if that matches the NEMA standard, but this won't tell you polarity of the coils. There are specialized analysis tools that can be used to measure polarity, but if this is not something that you are going to do frequently I doubt that it is worth the investment. Instead I would connect the motor in my best guess as to the proper connection, and then power it at reduced voltage and measure currents on the various leads.
-Jon
I'm not sure I understand what you mean by the polarity of the windings?
How would you power the motor at a reduced voltaege? Use some sort of adjustable voltage supply? What current values could you look at, when supplying a reduced voltage to verify correct connection?
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
By polarity I mean the relative connections of the various different leads.
In a 12 lead motor, you have 3 phase bands each split into half, and each phase band has 2 terminals. So each phase has 4 terminals, similar to a dual voltage winding of a single phase transformer. The two halves of the winding have to be connected with matched polarity for proper operation.
A simple continuity test will only tell you which terminal corresponds to which other terminal. If this matches what you would expect for a standard 12 lead motor, then I would be more inclined to guess that the 12 lead connection is correct. However since the continuity test can't tell things like relative phase angle between different windings, this would not be certain.
I'm not sure what to recommend as an easily available cheap variable voltage supply; I personally would use a VFD, but I have access to VFDs that I can program arbitrarily, including the DC rail voltage.
The currents that I would measure are on each of the 6 phase halves, and I would simply look for balance when the motor is spinning at no load and reduced voltage.
But IMHO the first choice is to simply get manufacturer's info on the motor, and connect per instructions. The next choice is to have a motor repair shop measure and figure out the connection. I apologize for jumping at what I would do if I had a motor in my hands and wanted to test it myself without the correct instruments. I spend too much time working with non-standard experimental motors
-Jon
In a 12 lead motor, you have 3 phase bands each split into half, and each phase band has 2 terminals. So each phase has 4 terminals, similar to a dual voltage winding of a single phase transformer. The two halves of the winding have to be connected with matched polarity for proper operation.
A simple continuity test will only tell you which terminal corresponds to which other terminal. If this matches what you would expect for a standard 12 lead motor, then I would be more inclined to guess that the 12 lead connection is correct. However since the continuity test can't tell things like relative phase angle between different windings, this would not be certain.
I'm not sure what to recommend as an easily available cheap variable voltage supply; I personally would use a VFD, but I have access to VFDs that I can program arbitrarily, including the DC rail voltage.
The currents that I would measure are on each of the 6 phase halves, and I would simply look for balance when the motor is spinning at no load and reduced voltage.
But IMHO the first choice is to simply get manufacturer's info on the motor, and connect per instructions. The next choice is to have a motor repair shop measure and figure out the connection. I apologize for jumping at what I would do if I had a motor in my hands and wanted to test it myself without the correct instruments. I spend too much time working with non-standard experimental motors
-Jon
chad lawson
Member
These motors are quite common on cnc machines for spindle motors. Where there are usually three contactors to run this motor. M1 takes three leads and powers them all the time. You then have a reversing set of lock out contactors that essentially switch the windings between delta and wye or even delta to star. In the machine tools this is done to give you two things is a low speed high torque motor application that can quickly change to a high speed low torque application. But they are also usually linked to a drive or vfd. Also six of the windings generally come out and are tied together in pairs. The switching contactors simply switch the phasing of the second set of leads.
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