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I am observing issues with linear actuator not moving and/or moving very slowly at highest speed setting. I am using a DC linear actuator with a speed control unit and rocker switch to extend and retract the actuator. The application involves dispensing material from a syringe at a controlled rate. The wiring is fairly straightforward and is shown below along with part numbers of components used. To limit the stroke length of the actuator in the extend direction, I am using an external PNP sensor to switch ON/OFF a SPDT relay.

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I have noticed a positive voltage (~10V) across output terminals of speed controller unit even when the speed knob is turned all the way OFF.

Any idea why the actuator doesn't move or move slowly at times even at full speed setting?

winny
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Rock
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1 Answers1

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There are a few things that could cause it to not move or move slowly, poor contact in the relay or switch, a problem with the speed controller, a problem with the power supply, or a problem with the actuator itself. You would need to monitor the voltage and possibly the current to the actuator to see what it is under normal operation, and when it's going slow.

If the voltage stays the same when it's malfunctioning as it is when working properly that would point to a problem with the actuator.

If the voltage is lower, then you would need to check further back in the circuit. Check the voltage at the speed control output, if it's good there check for voltage drop across the relay and switch contacts. If the voltage from the controller is low, check the supply voltage. If that's good the problem may be in the controller.

Of course make sure all your connections are good, it could be as simple as a screw terminal not tightened down all the way.

GodJihyo
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