Linear actuator limit switch replacement/repair

In summary: N force, 2 limit switches, with a speed of 5mm/sec and a 12V DC power supply. The motor may have stopped working due to a current surge and the limit switch burned out when the motor failed. The faulty switch needs to be replaced, which may require dismantling the unit. The diodes may also need to be replaced, and they can be found on popular marketing websites at a low cost. It is advisable to avoid using high voltage DC to prevent further damage.
  • #1
marellasunny
255
3
Linear actuator spec.: 400mm stroke, 6000N, 2 limit switches, 5mm/sec, 12V DC supply, BIBUS IP65 casing.

One of the limit switches of my LA (Linear Actuator) seems to have burned out. This happened because I accidentally plugged the LA leads into the AC mains socket (my LA is rated to run at 12V/24V DC). I could guess which limit switch burned-off from the way the relay erratically turned on-off everytime I reached one end of the LA. I would like to know the best way to replace the limit switch at the top-end. I've attached a pic showing the IP65 motor cover off. I want to seek advice before I take any of the motor screws off. How do I reach the limit switch at the top-end of the LA?

And some tips on where I could buy a replacement limit switch would help a lot.

Pics are in attachments.
Thanks!
LA repair1.jpg
LA repair2.jpg
 
  • #3
I am surprised that more was not damaged by the HV AC. Does the motor still work?
There is also usually a diode wired across the limit switches to make it possible to reverse back from the limit.
You will need to dismantle the unit to access the switches. Depending on construction, that may be a somewhat destructive process.
Once you have exposed the faulty switch you may find that it is repairable, it may be harder to find a replacement or make another fit.
Search the well known marketing websites for a replacement unit. It will probably be available at a low cost.
Take care. Avoid HV DC.
 
  • #4
Apologies for the late reply. The motor no longer works. Hopefully its because some passive component got burnt-up. 1 good thing that seems to have emerged is that I have come closer to understanding the inner workings of the linear actuator. Please find attached the pics with descriptions of the parts inside the actuator.
FYI- I've ordered the limit switches from China. They are very cheap and require soldering to assemble. This actuator is high precision but one has to take care of the power supply.
 

Attachments

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    LA repair3.jpg
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  • #5
You might as well replace the Diode S2M at the same time. It is rated 1000 Volt, 2 Amp. Do the same for the other limit switch.
 
  • #6
Tom.G said:
You might as well replace the Diode S2M at the same time. It is rated 1000 Volt, 2 Amp. Do the same for the other limit switch.
S2M implies surface mount? Then I'm thinking of using the 1N5408 as per the spec sheets. Yeah I see the smd diodes on top, numbers blackened out . Thanks for the tip.
https://en.wikipedia.org/wiki/1N400x_general-purpose_diodes
 
  • #8
marellasunny said:
The motor no longer works. Hopefully its because some passive component got burnt-up.
It is highly probable that the motor was destroyed, the limit switch burned out due to the current surge when the motor failed.
You need to see if you can get the motor working on 12VDC before you start buying and fitting replacement parts. The power diodes are the least likely components to fail.
 
  • #9
marellasunny said:
...numbers blackened out .

Aww, all the magic smoke leaked out.:H
 

1. What is a linear actuator limit switch and why is it important?

A linear actuator limit switch is a safety device that is used to control and limit the movement of a linear actuator. It is designed to stop the actuator from moving beyond a certain point to prevent damage or other risks. It is important because it ensures the proper functioning of the actuator and protects other components from potential damage.

2. How do I know if my linear actuator limit switch needs to be replaced?

There are a few signs that may indicate that your linear actuator limit switch needs to be replaced. These include the actuator not stopping at the designated endpoints, not moving at all, or making unusual noises. If you notice any of these issues, it is best to have a professional inspect and replace the limit switch if necessary.

3. Can a linear actuator limit switch be repaired instead of replaced?

In some cases, the limit switch may be able to be repaired instead of replaced. This typically depends on the extent of the damage and the availability of replacement parts. It is best to consult a professional to determine the best course of action for your specific situation.

4. How often should the limit switch be checked or replaced?

The frequency at which the limit switch should be checked or replaced depends on the usage and environment of the linear actuator. It is recommended to have it checked at least once a year and replaced if any issues are detected. However, if the actuator is used frequently or in harsh conditions, it may need to be checked and replaced more often.

5. Can I replace the limit switch myself or do I need a professional?

Replacing the limit switch can be a complex task and may require special tools and knowledge. It is recommended to have a professional handle the replacement to ensure it is done correctly and safely. However, if you have experience and knowledge in working with linear actuators, you may be able to replace the limit switch yourself.

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