Build Thread- Using G540 with power supply over 3.0 amps

[SteveS]

I am retrofitting a CNC Mill (16" by 24") with NEMA 23 motors. I bought a Gecko G540. A week ago I talked at length with their technical support for a while, but it was like being under an information waterfall, very refreshing and a lot at one time. At the time it seemed the G540 was perfect for what I needed.

I am ready to start wiring and connecting. The stepper motor data sheets have amps/phase as 2.12a at bipolar serial and 4.24a at bipolar parallel.

I rewired the motors from bipolar parallel to bipolar serial to reduce the amperage under the G540 3.0 amp motor rating. In changing to bipolar serial the mH goes up to 5.2 mH. I calculate the optimum voltage to 72v, which is well over the G540 maximum voltage of 50v. It is still 11 times my 24v power supply.

I only have a 24 V 5 A power supply at the moment. (The original power supply was integrated with the driver board and failed.) My plans are to get a 45-48v power supply in the future.

Is there any problem with the power supply being rated at 5a for use with the G540?

I am assuming the G540 will current limit down to the 3.0a rating of the board.

Is the limit resister still based on same formula? 2.12 * 1,000 = 2,120 ohms at 1/4 watt.

Steve.

OK: I just went for it and am mostly operational with no smoke escaping from the wires.

[PEU]

The power supply can deliver 5A but the gecko will only "request" what it needs, just keep the voltage within specs and you are good to go.

[ger21]

The G540 is rated for 3.5 amps, not 3.0. If you need to spin the motor fast, you may be better off wiring the motors bipolar parallel and running them at 3.5 amps. You'll give up 18% of the holding torque, but may gain torque at higher speeds.