Power Supply help

[dirtdiggler]

Hi Guys,

I'm trying to figure out the correct transformer and CAP I need to make a power supply for my servos and drives.

I'm going to have 4 Viper 200 servo drives and I need 120-130 Volts and 15 amps RMS to power my servos.

I'm a bit confused as to what VA number I need for the transformer.

I do have a 500 VA 115V power supply that came out of the machine but my guess is that this is not big enough?....It has H1 H2 H3 H4 with 0v/208v/230v/460v respectively on the input side and on the secondary side has X1/X2/XF(filter) .


Any help would be appreciated

[Al_The_Man]

Plugging the numbers into my calc sheet it looks like a 1.6Kva transformer for 60% duty cycle, 7300uf Capacitor for 5% ripple at 120vdc at 15 amps.
Al.

[dirtdiggler]

Hi Al,

Thanks for your help!

For the Capacitor, what volt reading would I need? considering I'm going to run 4 Vipers, for instance would I get something like a 7500uf 120V to run all 4 viper drives?

[Al_The_Man]

I would get a 160~180vdc min, or go with a 200v for enough margin.
Al.

[dirtdiggler]

Thanks for your excellent feedback again Al.

Do you or anyone else know where I can find a 1.6-1.7 Kva transformer?

I'm begining to think I might need break it up into seperate power supply's for each drive....yikes!

[Al_The_Man]

Are you using the original motors? If so, if the original supply is still there, I would tend to use it if possible, presumably it did the job so far for the same load & motors.
Al.

[dirtdiggler]

Hi Al,

It's a little complicated (for me) because I'm terrible at math. The original power supplies are broken up into seperate smaller ones to power the amplifiers and drives seperately. 4 of the transformers all have different VA ratings too. I might be able to salvage a few of the older transformers once I figure out exactly what I need.

For now I decided that I'm going to to break it down into seperate power supplies for each drive since finding a 1.7 KVA has been immposible.

Al, would you mind helping me out again with another calculation?

If I made a seperate PS for each drive/servo what size transformer and CAP would I need for each at: 120 Volts and 14 amps ?

Thanks in advance for your help.

-Kirk

[Al_The_Man]

Originally Posted by dirtdiggler Al, would you mind helping me out again with another calculation? If I made a seperate PS for each drive/servo what size transformer and CAP would I need for each at: 120 Volts and 14 amps ? -Kirk

Is each power supply 120vdc and 14 amps?
Al.

[dirtdiggler]

I'm not exactly sure if some of them are or not. What would the VA # on a transformer be for 120VDC/14 amps?

It's strange because there are'nt three of the same transformer for XYZ. There are about 7 transformers and they are mostly different sizes. Some of the transformers are rusty and the caps are starting to bulge out so I thought I would start over and replace them. I'm targeting 120VDC and 14 amps based on the servo spec.

[Al_The_Man]

What you need to supply is the motor ratings. Then some idea of what you need could be calculated.
Al.

[dirtdiggler]

Hi Al,


On my Servo motors this is what they say:

Brand PowerTron
RMS Amps: 14.6
Max RPM 6000
Tachometer: 7
Volt See/RAD K.V. ?233
Max Pulse Amps: 58.3
Rated Torque: 30
Max Volts: 146


-Kirk

[Al_The_Man]

Those are fairly large motors.
For 120vdc and 5% ripple @ 14amps my sizing program gives the following.
6800µfd
1.4kva @ 60% duty factor.
86vac secondary.
Al.