[storm2313]

The G540 is the best drive in its class pending its an all in one solution for motion control. It's fabricated by the leading company in motion control in the USA, and has an extremely low failure rate. I sell in excess of 20 of these units a month for this reason. I also find now, and then there are some things about the drive that I need answers to, and rely on Marcus for his excellent continued support.

I'm working on a new PC conversion design around the Gecko, and started reviewing the G540's internal fuse ratings. (This fuse carries a 7a rating), and the peak ratings on the drive. Well that's where I came to the conclusion somethings a miss.

If each of the 4 channels of the drive are rated to supply 3.5a, how can the drive provide 14a from a power supply if the internal fuse is only rated at 7a?? The answer was provided by Marcus (I provided his response in a snapshot to clarify this for everyone), and now makes sense. The drive's peak rating output is 3.5a per channel, but we should consider all the internal microstepping drives only able to provide the RMS rating which stands for Root Mean Square, or 70.7% of the peak value. This means the drives available current per channel is 2.47a. This essentially means we are able to through all 4 channels combined provide roughly 10a RMS of usable real word current to our motors.

Remember guys peak ratings are provided by the controllers manufacturers. They are reached through extensive testing, under short durations, and certain scenarios . This being clarified means your motors will not be receiving in this case 3.5a of current steadily.

You would never want your motors to receive their maximum current for longer than short durations as it makes them very hot, and increases wear on all components including the controller. All things considered you actually want the opposite. You should shoot for the less is more approach. If your system requires less amps to provide you the same outcome it's more efficient.
I hope this helps everyone understand the G540 a little better. Attachment 228940

Edealers Direct items in eDealers Direct store on eBay!
Vince

[Mariss Freimanis]

The reason is a little different than that. Motor currents are 3.5A and there actually is 14 Amps total circulating through all 4 motors without any time limitations at all. The G540 motor drives are switching-type PWM drives; motor currents are always higher than the power supply current. At low speeds the PWM duty-cycle is around 60%. This means the drive pulls 3.5A from the supply for 60% of the switching cycle and then pushes that same 3.5A back into the power supply for the remaining 40% of the switching cycle. This happens 20,000 times a second. The average current drawn from the power supply is 0.7A for a motor that has 3.5A circulating in it's windings. (60% * 3.5A - 40% * 3.5A = 0.7A)

You can also look at it intuitively: 3.5A at 48VDC is 168 Watts per motor and it's enough heat to catch the motor on fire. Since that doesn't happen then something else is going on.

Mariss