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Motec Dual half bridge question

Practical Motorsport Wiring - Club Level

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Hello sorry if this is a silly question but is it possible to use a motec DHB to control two headlight retract motors (that run in the same direction)?

I have a motec pdm30 which I was hoping to power/control the motors but will only work with one motor via the wiper specific output (output 9)

Many thanks

When you say that they run in the same direction, are you meaning that the motors do not reverse direction to lower the lights? i.e. They work on a cam type setup and only run in one direction to raise and lower the lights?

If that is the case, then the DHB could do this, with one motor on each of the outputs (as long as the current draw remains below 20A). If the motors need to be reversed, a single DHB could also do this, as long as the current limit is not exceeded.

How are you controlling the travel of the motors? is there a limit switch or similar that provides a signal to the controller that says that the lights are parked or fully raised?

Hello yes they only run in one direction similar to a wiper motor, they have two park switches one for when the head light is in the up position and one for when its in the down (I've attached a video demonstrating the headlight motor functioning on the motec pdm output 9)

If I use the motec DHB can that be controlled through the pdm?

Attached Files

What is the current being drawn through the PDM to drive the motor? The DHB can be controlled by the PDM, but it seems to be a potential over kill to have a DHB controlled by an output on the PDM if the PDM could just drive them directly.

It draws about 1.5 - 3 amps

The problem I'm having is that the pdm can't drive two motors. I've attached a video of what happeneds when two motors are hooked up one is attached to output 9 and the other is on a different 8 amp output (they both wired the same and have the same logic only difference is the outputs)

You see one motor that's wired to output 9 works as it should and the other just constantly on and pauses a spilt second when it triggers the park switches then continues to run.

Can you post your configuration thanks.

Here's the config file

Attached Files


Have you swapped the motors over so that the LH motor is on Output 9 and the RH is on Output 5? What where the results of this? What happens if both are run off of 8A outputs other than Output 9? Do they both have the same Park signal coming in?

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