using ssr to turn motor transformer on and off

Using Arduino Project Guidance
1

Hello - Is it possible to adjust speed of a dc motor with a ssr? My thought was to connect the ssr to the arduino and send high and low signals to it which in turn would turn the power on to a dc power supply hooked to the motor. How fast can this be done? Does the transformer hold to much residual power to make this practical? I only ask because I already have the parts to make this. I assume that on and off would work with no speed control?

Anthony

2

aiannar974:
Hello - Is it possible to adjust speed of a dc motor with a ssr? My thought was to connect the ssr to the arduino and send high and low signals to it which in turn would turn the power on to a dc power supply hooked to the motor. How fast can this be done? Does the transformer hold to much residual power to make this practical? I only ask because I already have the parts to make this. I assume that on and off would work with no speed control?

Anthony

You are confusing yourself by calling a DC power supply a transformer. A transformer is an AC only device and cannot supply ANY DC for any reason. Your Power supply probably has a transformer in it to reduce the mains AC voltage to a lower voltage, which is then converted to a DC voltage that can run your DC motor.

Yes, you can somewhat control the power supply with an AC SSR. It is no different than just setting there and turning the power switch on and off. Try that before doing anything else. See how much control you have with the power switch, then you can replace the power switch with the AC SSR.

There are both AC and DC SSR devices available. If you are serious about this, get a DC version of the SSR that will handle the motor current and use it.

Paul

3

I guess you're talking about switching the AC on & off? I wouldn't recommend that. It might work if you have enough inertia (such as a flywheel) but if the DC power supply is regulated the regulator will "fight" what you're doing and you might over-stress the power supply.

A [u]MOSFET driver circuit[/u] can be used with PWM to control the speed of a DC motor.

4

Hi,
What are the specs on the motor?
What current and voltage is specified?

Thanks.. Tom... :slight_smile:

5

Much easier and common approach to use pwm on DC side to control the motor speed . Units that can handle several amps cheap as chips on eBay etc for a couple of dollars. No microcontroller required. Simple to interface to Arduino if necessary.

6

The other day someone asked about controlling a DC motor with thyristors... that's yet another option... (but the way the original question is posed, quite certainly not something for the OP to pull off successfully and safely).