Single phase motor drive control

[shvstr]

Hello,

I am Shivkumar Nistala, Electrical Engineer. I am looking to automate the packing system. I have a single phase, 60 hz, 115VAC motor running a conveyor mechanism. I want control the speed of the motor in such a way that the motor would accelerate within a few milliseconds each time it starts. I was looking for an AC drive which could serve this purpose. All the drives that I found during search have a 3 phase output. I want a single phase input and single phase output drive.


Please recommend a drive which would be suitable for this application.

Looking forward to your response.

Thank you,
Shiv

 

[zbang]

You've left out a lot of detail, like the size of the motor. If it's a 115v motor, it's 1 HP or smaller, yes? Is there any reason not to use an across-the-line starter (if you don't need over-current protection, how about a simple contactor)? Or, do you want to control the speed of the motor while it's running? There are single-phase VFDs for this. Depending on the actual load, you may never "a few milliseconds" acceleration.

 

[GoldDigger]

Possibly the only motor and drive that could do that would be a stepper motor.
After all, one cycle of 60Hz AC is already 16ms.
Better might be to combine a continuously running (or prestarted) motor (and maybe with added flywheel mass) with a magnetic clutch.

 

[junkhound]

Like GD implies, your "within a few milliseconds each time it starts" indicates some lack of electrical engineering knowledge.

Be more specific and factual.

A few microseconds implies many kW and stuff getting thrown off the conveyor :lol:

 

[Jraef]

1) Although there are a few VFDs that will operate single phase motors, they only work on a small subset of single phase motors, and those are ones that in general have low to very low starting torque capabilities. If your motor is not one of these already (PSC or Shaded Pole) you cannot use the VFD. So if youust change the motor anyway, change to a 3 phase motor.

2) As a general rule, a VFD will EXTEND the acceleration of the motor and load, not decrease it. Across-the-Line (DOL) starting is in general the fastest a motor can accelerate, certainly a single phase motor. If your motor is not accelerating fast enough now, it's because it is too small. But even if you grossly over size it, milliseconds is a very difficult goal for an inductionotor. It takes roughly 16 milliseconds just to establish a magnetic field; to make the motor into a motor instead of a boat anchor.

3) If you have absolutely determined that you MUST accelerate onilliseconds, I think a Permanemt Magnet Brushless Servo motor and drive is your only hope, Ana forillisecond acceleration, plan on grossly over sizing it. And go get a loan at the bank, it's not going to be cheap.