Dynomotion

Group: DynoMotion Message: 9364 From: az9633@ymail.com Date: 3/24/2014
Subject: Snap Amp Disable
When I use the Disable command with my Snap Amp the motor seems to partiially disable.  That is there is no torque on the motor but if I spin the motor there is resistance like a Dynamic brake is active.  If I set the SnapAmp current to less than 7 then the motors actually freewheel but I notice that the amps are faulted.
I'm using brush type motors.
Can you explain?

AZ
Group: DynoMotion Message: 9366 From: Tom Kerekes Date: 3/24/2014
Subject: Re: Snap Amp Disable
Hi Az,

That sounds correct.  When SnapAmp Disables it commands PWMRx=0 which is basically zero volts.  Zero Volts is the same as a short circuit.  The braking action should be very similar to if you just short the motor leads.  It is like a shorted generator.

Setting the Peak Current Limit that low generates a Fault which open circuits all the FETS.  So the motor should spin freely.

You should also be able to command zero current with PWMCx=0.  This should also generate no torque and the motor should spin freely.

Regards
TK