G250 Drives with 56V Power Supply?

[Adamj12b]

Hello All,

Its been about a year since Ive worked on assembling my Plasma cutter I am building. I had bought 6 of the 250 drives when they were intruduced at the low price, but never used them.

I have been going through my machine parts and have realized I have the perfect power supply for my system, but the voltage is a little bit high.

The power supply is made by Slo-Syn. It is 56V, 7.7A with 120 or 240V inputs.

My question is this too high for the 250 drives? I remember reading somewhere before that they have a max voltage of 60V.

As for motors, I will be using 2 - 3.5A steppers from Keling(KL23H2100-35-4B) and one smaller motor that I am unsure of right now. I believe it will be 1A.

-Adam

[Crevice Reamer]

Hi Adam.

Mariss has made it clear that there are good reasons to limit Voltage to 50V--Like back EMF tolerance for instance.

That being said, you might get by with only a couple of Volts over the limit.

A. If that is a switching PSU, it may be possible to adjust the Voltage lower.

B. If not a switcher then maybe, with a full load, the Voltage will drop down to within limits.

Make sure your third motor fits the PSU envelope.

CR.

[CoAMarcus]

Adam,

The drop dead voltage of the G250, G251 and G540 is 63VDC. If you have a 10% ripple with a 56VDC power supply you are now looking at 61.6VDC; if you account for a 5% component tolerance you have a maximum voltage of 59.85VDC on that particular drive. Your power supply is then too large and the drive will blow up. It is not recommended to take the PS voltage above 50VDC as you will be approaching the Vne of the drives very quickly.

Marcus

[Adamj12b]

I finally had a chance last night to check the open voltage of the supply. Its defiantly a 250 killer at 62.8V.

I then tried wiring the 120V into the 240 inputs to cut the voltage in half. This is now giving me an open voltage of 30.7V. I will also have to keep an eye on the transformer as now instead of running primary coils in parallel for higher current, I am running them in series. I believe there is a thermal cut out in the transformer, but I will watch to make sure im not cooking it. Its lower then I wanted, but its also free....I will see how it works and if its not enough I will have to get something else. Keling sells a nice 48V switching supply that I like.

-Adam