the only reason someone would use high voltage machine / motor is to lower the Amps, what is the existing speed and capacity of the car ? if the HP is greater that 40HP or even 30hp its better to go with high voltage . smaller drive and better price on the controller , the down side is you need a step up transformer .

Only reason to do that would be if the motor voltage is higher than line voltage. Alot of gearless pm motors are in the 300-400v range and if your line voltage is too low, the dc bus won't be able to charge to a high enough voltage to be able to run the motor.

If your going to use a motor especially an induction motor that's the same as line voltage, there's no benefit. Your control transformers are going to kick it down to 120 or less anyhow for all of the controls. And I've never seen a door operator run on higher than 220/240. Most new operators are fine with lower voltage.

And yes, you'd need a step up iso transformer to do this.

The existing motor is 460v 10HP. With FLA= 14.3

100fpm 2500lb cap

HW is giving us a new 208/230/460 20HP motor .
AMPS - 29.2/28.2/14.1

With geared traction machine that says 7.3 HP

Sounds like it can be wired up low voltage and be good to go

But then my amps will be 29.2? Looks like we need the 460v to keep similar FLA ?

This is true, if you halve your voltage and keep your hp the same your amperage will roughly double. I guess it depends on your goals. Is higher FLA bad? Wouldn't you just need to pull wires to the motor a little heavier?

Your FLA amps to the motor would be higher. But if your motor HP is staying the same, the line current supplying the controller would not change. The only change in amperage you'd see is between controller to motor. The old setup the current supplying the controller was just as high before but was being supplied to the transformer primary, and on the secondary side (controller to motor) the amps were lower due to higher voltage. But power consumed is power consumed regardless of voltage.

Sounds like a Solid setup with alpha and HW

Are you going with the GT-11 machine?

Yes GT11.

I just don’t want to trip our main line breaker .. I think we should keep the existing transformer and the 480v to controller. This way amp is same as now

It doesn't make a difference to me what you end up doing, but I think your missing what I'm saying about power being equal. A transformer simply transfers power, it doesn't increase or reduce it. It changes the voltage/current relationship. The amperage is going to be the same through your disconnect regardless of whether you keep the transformer or ditch it. Because the voltage through the disconnect is not changing and the power required is not changing the current is not changing. The previous system only seen a reduction in current on the secondary side of the transformer, which is the controller side. This is why the data tag on a dual voltage motor has 2 amp ratings and 2 voltage ratings but only one HP rating. I'm speaking of Power in the electrical meaning of the word.

Keeping the transformer wouldn't hurt anything, but it is unnecessary. Unless you want to keep it for helping reduce harmonics. But if alpha is supplying a line reactor in the controller(they should be), that is sufficient.

Thanks EE. Got it

There is a couple potential perks to keeping the transformer, such as it serving as an iso transformer to help reduce voltage spikes as well as harmonics and maybe downsizing the drive to save a few bucks and saving a few bucks on motor wiring size

Do you see any issue with keeping the existing Otis transformer ?