relay advice required

[oOo Les oOo]

Hi,

I looking for some help, I have a device that when conditions are met it turns on a small motor to provide vibration feedback. The current feedback is very weak and I would like to add a much larger motor with speed controller to give adjustable feedback.
Would it be safe to add a relay replacing the motor that would turn on the replacement motor. I have measured the voltage across the motor when activated at 3.8 volts dc.

As-is

PCB - Motor

New

PCB - Relay - 12v psu - Speed controller - Motor

If this looks ok can someone recommend a relay

Thanks

 

[Reloadron]

Depends on a few things and for starters how much current the new motor will draw.

Ron

 

[oOo Les oOo]

I was looking at maplin.co.uk for a new motor, I have a choice of two one is 1400ma and the other is 2850ma

 

[Reloadron]

So the load can be from 1.4 to 2.85 Amps. For what you want to do, and in keeping it small, I would think about looking towards a small automotive relay that can be easily had in any automotive parts store at a reasonable price.

Ron

 

[oOo Les oOo]

Thanks, I was worried about potential damage to the other electronics on the PCB due to replacing the motor with a relay

 

[Reloadron]

Just make sure you place a diode in parallel with the relay coil and observe polarity with the diode. Cathode of diode to + side and anode to the - side. You don't want an inductive kick from the coil when it is de energized hitting your components.

Ron