[robhrzic]

I am trying to build a power supply using the pmdx power prep module which is rated for up to 80 VDC at up to 20 amp use. See here:

http://www.pmdx.com/PMDX-135/index.html

I will be using this power supply using (3) G320 Geckos, driving Keling Technologies' KL34-180-90 servo motors. See here:

http://www.kelinginc.net/KL34-180-90.pdf

I am having a little difficult selecting a proper transformer. If I understand correctly, I need a 55 VAC secondary to attain approximately 76 VDC ((55 VAC x 1.414)-1.5=76.27 VDC). I am having trouble figuring out what the current rating of the torodial transformer should be (800 VA, 1000 VA, 1500 VA, etc...).

I would also eventually like to add a fourth G320 and servo for control of a fourth (A) axis, and would like to assure that I have some current to spare in the future.

Could someone please assist me and reccomend a suitable transformer, and hopefully explain how they got to their conclusion?

:withstupi

[Al_The_Man]

This guy builds and sells on ebay e.g. item#7540255036. This one should fit the bill, the continuous rating for the motors are 7.8A each. It is highly unlikely that you will be running all three or four motors instantanously at continuous rating.
The one listed is 800VA I would think 1kva would be max. you would need.
The nice thing about these toroids is that winding can be modified or even added simply.
A search of the forums should come up with many examples.
Al.

[robhrzic]

Thanks for the input Al_The_Man.

I ordered the 56+56V 1KVA Toroidal Transformer from AnTek, Item #270152210432 on eBay.

[ericravi]

Thanks for the input Al_The_Man.

I ordered the 56+56V 1KVA Toroidal Transformer from AnTek, Item #270152210432 on eBay.

Servo Motor are also called Control motors. They are used in feedback control systems as output actuators and does not use for continuous energy conversion. The principle of the Servomotor is similar to that of the other electromagnetic motor, but the construction and the operation are different. Their power rating varies from a fraction of a watt to a few hundred watts.

This kind of servo stabilizer consists of an AC synchronous motor coupled with an Auto Power Transformer