Hi,
I have a brushed DC motor from an old hitachi drill (dv18dl) which I would like to control but I am unsure on whether the VNH5019 would be suitable? The motor has a running current of 2.2A at 15V and a start up current of about 6A.
I am hoping to run the motor at very low speeds (maybe 60rpm) and for only about 1 minute at a time.
Cheers
Hello, Gillies.
I moved your post to the “Motor controllers/driver and motors” section of the forum since it seemed more appropriate.
The VNH5019 driver would probably be fine for that motor, but to be on the safe side, we typically recommend choosing a motor driver that can handle the stall current of your motor. Drill motors usually have fairly high current draw in my experience, and in general a brushed DC motor can draw many times its running current when stalled. How are you measuring the start-up current? The spike at start-up can be very fast, so it can often be hard to measure accurately. You might try powering the motor from a low voltage (e.g. 3V) and stalling it, then extrapolating to see what the stall current would be at 15V. For example, if you stall it at 3V and get 2A, it would draw approximately 10A when stalled at 15V.
Brandon
Hi Brandon, thanks for your response. I got to excited and bought this drive anyway haha.
I am measuring the current with an analogue amp meter so your probably right in that I’m not catching the true start up current as the analogue meter would not be quick enough. Will the drive be damaged if the start up current is above 30amp or will the drive protect it self against large start up currents?
I am planning on protecting the drive by placing a 2amp c curve cb on the input side of drive which which takes along time to trip at 2.2amps (which is fine for the time the motor running time) and trips very quick at 10amps so I am hoping this would be sufficient to protect the drive against any stall currents/overcurrent.
But is it correct that the vnh5019 drive also has overcurrent protection which will stop the motor if an overcurrent is reached?
Also if I run the motor really slow, will it draw more current than running it at full speed? Could this be an issue?
Thanks again Brandon
Hello.
As you mentioned the VNH5019 does have some protections, but note that it is possible for a spike to happen quick enough to cause damage before protections can kick in. In your case, I suspect it will be fine; the current draw will be proportional to the operating voltage, so if you are operating it at a low speed (i.e. low duty cycle), it will draw less current. In fact, ramping up the speed is generally a good way to help prevent large current spikes.
Brandon
