gecko g540 < resistor for current limiting, answered>

[Kutton]

What amps must motor draw to eliminate a resistor?

[Gary Campbell]

Eliminate which resistor?

Current limiting resistor on the drive? That info is in the G540 manual.

Resistor between step/direction signal and the drive? Not needed, use the DB25 connector

[Richards]

The manual says this about the current limiting resistor:

"Wire your motors to the included DB9 solder cup and secure the backshell connectors. If your motors are rated below 3.5A you
must use a current set resistor across PIN 1 and PIN 5. The resistor is calculated by taking the current in amps and multiplying
by 1000. If your motor is rated at 2.8A per phase you will have to use a 2.8K 5% 1/4W resistor. If your motor is rated at 3.5A or
above you can safely not use a current set resistor; however, your G540 will not go into current standby mode which will result
in increased motor heating."

I use current limiting resistors with my G540, even when using motors that are rated at 3.5A and above. With a resistor, the G540 can enter standby mode.

Even though the manual also warns against using "wire plugs" (3. Do not use wire plugs for the main terminal block. Only put stranded wire with a gauge range of 14 – 24 to make proper contact and not stress any terminals.), I always crimp ferrules onto stranded wire. It's just too easy to have a loose strand of wire bridge into another terminal. With ferrules, that has never happened.

[martyscncgarage]

The manual says this about the current limiting resistor:

"Wire your motors to the included DB9 solder cup and secure the backshell connectors. If your motors are rated below 3.5A you
must use a current set resistor across PIN 1 and PIN 5. The resistor is calculated by taking the current in amps and multiplying
by 1000. If your motor is rated at 2.8A per phase you will have to use a 2.8K 5% 1/4W resistor. If your motor is rated at 3.5A or
above you can safely not use a current set resistor; however, your G540 will not go into current standby mode which will result
in increased motor heating."

I use current limiting resistors with my G540, even when using motors that are rated at 3.5A and above. With a resistor, the G540 can enter standby mode.

Even though the manual also warns against using "wire plugs" (3. Do not use wire plugs for the main terminal block. Only put stranded wire with a gauge range of 14 – 24 to make proper contact and not stress any terminals.), I always crimp ferrules onto stranded wire. It's just too easy to have a loose strand of wire bridge into another terminal. With ferrules, that has never happened.

Richards is correct, you always use the resistor so the drive can idle the steppers to keep them cool.
The G540 manual goes through all of this. Take a few minutes to read through it:
https://www.geckodrive.com/amfile/file/ ... uct_id/14/

[Kutton]

Appreciate all the feedback]. Have decided to use resistor.

[eswakon@eas-eng.com]

Richard, I too have 3.5Amp motors attached to my G540. I don't have any resistor installed. What resistor are you using?

[Richards]

On the G540, use 1000 X the Amps, so 3.5A X 1000 = 3.5K. I use the closest standard 5% resistor, which is 3.3K.

[martyscncgarage]

Richard, I too have 3.5Amp motors attached to my G540. I don't have any resistor installed. What resistor are you using?

3.5a motor requires a 3.5k ohm 1/4w resistor