Different steppers!

[GEFR]

The steppers I have from Hobbycnc are 23-84-DS 84 oz/ins 6Vdc 1.2A 5Ohm.and these work fine. I have some smaller motors remaining from my original earlier experimentation and would like to build a small demo/trial machine driving these motors from my existing software and drivers. My question is that if I attempt to drive my original 12 oz/in steppers coil resistance of 75, 0, 75 ohms (from Milford instruments UK) with the Hobby cnc driver is it possible to damage the driver due to attempting to drive current into a high resistance load. Like for instance say you operated the drivers to an open circuit. This could be compared to operating an audio Amp with unsuitable speakers or none at all connected. I know Hobbycnc cannot be held responsible as the steppers are not of their supply but I would like an opinion.
By the way I am starting to do three axis stuff and have been running with only three of my steppers connected. I realise that the fourth stepper driver may not know I have no stepper connected and may well be trying to drive a 50% position holding current into what amounts to aan open circuit! Any comments?
Regards
Ken

[neilw20]

Driving into a high resistance or open circuit is OK.
Old audio amplifiers had the problem because they had an output transformer, which could generate high voltages like a car ignition coil if unloaded.
The stepper drives are direct driven and this is not a problem.
What is a problem is disconnecting a stepper motor while it is powered.
This can generate high voltages like the ignition coil.
This can damage the controller.

At your own risk (for the weak hearted, or cardiac challenged):
To see the effect, get a SMALL 12v relay and holding both wires to the coil in your freshly washed hands, touch across the terminals of a 9 volt battery.
Get the idea of what will kill a controller if the terminals are loose?