Using Kflop and Kanalog in control panel to drive stepper motors. 4 Stepper motors are rated 5.7 volts , 3.5 amps and 22 (mH). Using Gecko G210 drives. Gecko drive is rated for up to 80 volts. Gecko recommends power supply voltage should be no less than 4 times or no more than 25 times the motor’s rated voltage. I first started with regulated a 48 volt power supplies but the Gecko drive went into fault condition and it turned out to be back emf on slow down of motor.

So I added the Gecko recommended Return Energy Dump circuit and added a diode, led and capacitor to the Gecko Return Energy Dump circuit so I could see when the Gecko Return Energy Dump circuit was shunting EMF and working. (see circuit below) It worked great and fixed my problem, when the stepper motor decelerated at a quick rate the Return Energy Dump circuit turned on and I could see the led light and slowly dim, it works great. Gecko states this circuit protects stepmotor and servomotor drives from damage during periods of energy return when operating near maximum rated voltage.

After posting on this forum my problem I revcieved help to fix the problem and I received several recommendations to change the regulated power supplies to unregulated diode/cap power supply.

I upgraded to an unregulated 70 VDC 800 watt power supply which is near maximum rated voltage of the Gecko G210 and installed the Gecko Return Energy Dump circuit, one on each of the 4 stepper motors.

I am bench testing everything with the steppermotors c-clamped to a table with no mechanical load that would increase the back EMF.

Ran the motors and the Gecko Return Energy Dump circuits worked fine then after running at different speed several times the Gecko Return Energy Dump circuits started burning up with clouds of smoke. I saw the LED's stayed lit telling me the TIP 147 transistor shorted out and the 33 ohm resistor was burning up because the shorted transistor kept power through the resistor.

Gecko circuit

Circuit I added the diode, resistor, LED and capacitor

I don't know if the back EMF voltage or current is now the problem with the higher voltage power supply, the TIP 147 transistor in the Gecko Return Energy Dump circuit is rated for 100 volts at 10 amps.

Does anyone have a suggestion on a circuit design or a transistor to use in the Return Energy Dump circuit hat would handle the higher voltage and current of the back emf. I do want to stay with the higher voltage power supply.

I am now afraid not to use a Return Energy Dump circuit for fear of burning up the Gecko drives, the cloud of smoke from the Return Energy Dump circuit raises my concern.

Thanks Joseph

 

Your posted schematic is unreadable.

 

Gecko drives are one of the most popular in the DIY world, have you ran it past Gecko support?
Max.

 

View attachment 132771
View attachment 132772

Your posted schematic is unreadable.

 

Gecko drives are one of the most popular in the DIY world, have you ran it past Gecko support?
Max.

I will call them Monday they have been very helpful in the past.