eBay TB6560 Stepper Motor Driver Boards

[irving2008]

This board is ment to be rated upto 36vdc, So I tried using my 36vdc 10A PSU.

I set the board to it's lowest current setting on the DIP switches to make sure I did not burn out or over heat my stepper motor, I am only testing X-Axis atm.

Powered up the board, and all the lights and the fan came on, Turned it all off and, when I next turned it back on, I was greated with a nice pop / bang, with sparks, and blue / white smoke.

Part of the Z-Axis TB6560AHQ had exploded, Oh Joy.

I have since looked at some of the datasheet for the Absolute Maximum Rating.

L7812CV - 35 Volts Absolute Maximum Rating.
L7805CV - 35 Volts Absolute Maximum Rating.
TB6560AHQ - 40 Volts Absolute Maximum Rating.

I will post a pic of the poor TB6560AHQ chip once I have uploaded it to my site.

Can you turn down the power supply? Mine goes down to 32 and up to 40v. it could be that back-emf from the motor had damaged the chip by spiking the supply - I'd limit that board to a 30v supply if it has regulators on-board unless they have an additional dropping zener diode in series. On my board you can see spikes of 65v on deceleration, so I have a snubber (basically a 36v zener and a low ohm resistor) across the supply. Another solution, shown in the attached schematic uses a transistor to the same effect...

[Mad Professor]

Here is a pic of what is left of the chip.



My 36vdc PSU is not adjustable.

I now need to start looking at ways to limited the voltage and spikes.

I was looking at using a zener diode and Metal Oxide Varistor to deal with the spikes.

But I still have to look into it more.

[irving2008]

Thats pretty impressive... any collateral damage as far as you can tell? I'd strip the chip off the board and then retest on the 13v supply and confirm other voltages are as expected...output of regs, logic levels, etc. and compare the voltages on equivalent pins of the remaining drivers - without motors attached.

No point in replacing it if there is more damage...

Alternatively you could send it back...

[Mad Professor]

I have removed the damaged chip, and have powered it using my adjustable bench PSU, all the lights came on, no more smoke.

So it looks like only the one chip got damaged.

[Tom]

Can you turn down the power supply? Mine goes down to 32 and up to 40v. it could be that back-emf from the motor had damaged the chip by spiking the supply - I'd limit that board to a 30v supply if it has regulators on-board unless they have an additional dropping zener diode in series. On my board you can see spikes of 65v on deceleration, so I have a snubber (basically a 36v zener and a low ohm resistor) across the supply. Another solution, shown in the attached schematic uses a transistor to the same effect...

Hi Irving,

That snubber circuit is very interesting... It's just what I need. I'm running one of those 50V power supplies that Kip found in "unregulated" mode at 43V. My drivers will smoke at 50V, so I'm nervous.
Can you point me towards any online material that would help size the components to dissipate the sort of spikes I'm likely to see?

Sorry to hijack! (maybe Irving's tip will save a few more driver boards... :)

Tom

[irving2008]

Hi Irving,

That snubber circuit is very interesting... It's just what I need. I'm running one of those 50V power supplies that Kip found in "unregulated" mode at 43V. My drivers will smoke at 50V, so I'm nervous.
Can you point me towards any online material that would help size the components to dissipate the sort of spikes I'm likely to see?

Sorry to hijack! (maybe Irving's tip will save a few more driver boards... :)

Tom

Tom,

Yes, sadly I wasnt able to find an easy way to turn the volts on those down as they do some strange things with the internal reference line that doesn't follow the application note for the chip they use. I managed to blow one up quite spectacularly!

When I said zener diode I really meant a transient suppressor diode (transorb), such as these from Vishay. But i think clamping to 50v from a 43v supply might be tricky. A zener will clamp, but wont catch transients. you could use a 47v zener as a clamp with a 48v transorb in parallel to catch spikes, with a series low ohm resistor as a current limit between the supply rails. Farnell sell the transorbs, about 30p a go.

[Tom]

When I said zener diode I really meant a transient suppressor diode (transorb), such as these from Vishay. But i think clamping to 50v from a 43v supply might be tricky. A zener will clamp, but wont catch transients. you could use a 47v zener as a clamp with a 48v transorb in parallel to catch spikes, with a series low ohm resistor as a current limit between the supply rails. Farnell sell the transorbs, about 30p a go.

Thanks Irving!

That's just the right amount of info... I REALLY don't want to smoke these drivers, so I feel some internet research, followed by electrickery, coming on....
There's time because I'm not cutting in anger yet - just aligning, and debugging....

Cheers,

[Mad Professor]

Today I have been able to find some free time to do some basic current testing using my bench power supply, and USB Oscilloscope.

Using the oscilloscope across the current sence resistor I get the following results.

Bipolar Parallel
DIP Switches 1-2
ON/ON: 0.469v avg / 0.33ohm = 1.421a.
ON/OFF: 0.313v avg / 0.33ohm = 0.948a.
OFF/ON: 0.234v avg / 0.33ohm = 0.709a.
OFF/OFF: 0.078v avg / 0.33ohm = 0.236a.

[irving2008]

Today I have been able to find some free time to do some basic current testing using my bench power supply, and USB Oscilloscope.

Using the oscilloscope across the current sence resistor I get the following results.

Bipolar Parallel
DIP Switches 1-2
ON/ON: 0.469v avg / 0.33ohm = 1.421a.
ON/OFF: 0.313v avg / 0.33ohm = 0.948a.
OFF/ON: 0.234v avg / 0.33ohm = 0.709a.
OFF/OFF: 0.078v avg / 0.33ohm = 0.236a.

That looks about right... i assume by average you mean RMS, so the peak current will be around 2A. Can you post waveforms as discussed?