[springer-]

Here is the info....

10hp 3 phase induction motor
20hp Hitachi VFD
Going to wire it for Single phase on the line side
I posted a picture of the tag for the motor and the wiring configurations for the motor

Note the 2 symbols, the triangle and the "Y". I am not sure which configuration to use or what the difference between them is. Any insight would be helpful.

This is being used in a Lathe if that helps any.

[Eldon_Joh]

my guess is the 220/440 volt nominal high/low voltage refers to the WYE connection.

this means the delta connections are 138/254 volts.

however, it may be the other way around.
meaning the 220/440 v connections are delta and the wye connections would make 380/761 volts.

[springer-]

Hi, thanks for the reply. Actually the motor can be wired for either WYE or Delta in either 220 or 440V.

I am definitely using 220 since it is what my line voltage is. The question is what would the VFD prefer?

[mactec54]

Hi, thanks for the reply. Actually the motor can be wired for either WYE or Delta in either 220 or 440V.

I am definitely using 220 since it is what my line voltage is. The question is what would the VFD prefer?

Go with Delta 220V configuration

[springer-]

After more research it seems this motor was used in a "Star-Delta" configuration. The "Star" or WYE or "Y" can start the motor with less current draw but doesn't reach full torque potential in this configuration. The "Delta" or the triangle drawing gives full torque but draws lots of current to start the motor up. A hybrid configuration uses the "Star" to start the motor and when it gets to about 80% it switches to "Delta" configuration. In the old days this was the best of both worlds, low current start and max torque when running.

I called the tech guy where I purchased the VFD and asked him the same question and he didn't really give me a straight answer, saying to uses it the way it was on setup previously. The VFD doesn't do "Star-Delta" so that really didn't apply. Mactec54 did give the correct answer but I need to know why. I can't just follow direction, it has to make sense or I am not doing it. No offense to mactec54 but I have no idea who he is or what he knows.

I continued the search for answers. It comes down to the VFD can control the startup current so in a Delta config it isn't going to overload the VFD. When it is up to speed the Delta config will also allow the max torque. So Delta config is the answer.

Since I am going to run this 10hp 3 phase motor on single phase there are some additional changes that have to be made in the VFD. Basically it has to be derated by half so as to not overload the VFD. Additional consideration have to be made for the input line power rating. Since it will still draw the same current but it will be drawing from 2 legs instead of three, the power line has to be able to support 1/2 more current. Since I don't intend to operate it anywhere near full torque it will never see the added current. I am going to stay with a 80 circuit and use a 75 amp breaker. We'll see how it goes.

[mactec54]

springer-

You don't have to worry about the high draw with running Delta configuration,the VFD uses a soft start, so Delta as I said is the only setup you can use, derating is usually 30% to 40% at most, so you will be fine with what you have suggested for wiring, you may be a little over what is needed, but that won't hurt anything, your VFD is really to big for the job, 15Hp would of been more than enough, the 20Hp will be ok but was not needed

If the VFD faults out when starting, you just increase the acceleration/ramp up ( time ) same for deceleration, you adjust this also, ramp down ( Time )