How To Repair A Microswitch
Originally Web posted Thursday, 8 January 2009.
Content last modified Saturday, ix January 2022 .
Microswitch Repair
Why?
Why repair a microswitch (a.1000.a. "basic switch" or even "snap switch") when they are inexpensive and readily bachelor? Several reasons come to mind:
- Some microswitch variants are "special", with rare or unique specifications. They may non be readily bachelor, or available at all!
- Some "special" microswitches are far from inexpensive.
- Repairing a microswitch vs. buying a new one reduces waste product.
- You lot tin legitimately use the phrase "Going all Cuban"[1]. As in "I went all Cuban on that microswitch, and repaired information technology".
- It tin exist a fun and rewarding experience!
How?
This instance study covers the Honeywell Micro Switch® brand model V3-2414-D9 microswitch. In tardily December 2008, there was no reasonably available substitute for this switch, which was needed to repair a dwelling heating furnace. The techniques described and shown here should apply to virtually or all V3 Micro Switch®es directly, and should be useful guides for other makes and models.
Step one: Open up the Switch
Careful report of the construction details of the microswitch will probable be needed. Micro Switch® brand standard-size switches like the V3 and V7 (and other) series are held together past 1 rivet. Drilling the back end crimp off the rivet (a standard technique for removal of this sort of rivet) will allow the rivet to exist removed:
On most designs, the switch "half" on the side with the rivet caput(due south)(opposite the side drilled out, and ordinarily with the electrical specifications) is far less than half the thickness. Lift this department straight off, and one should see something like this:
In the Micro Switch® V3 pattern, null "boinks out": every role of the switch mechanism is visible and stays in place. Nevertheless, the parts can fall out, so care is required.
Step ii: Clean the Contacts
- Pull out the normally open contact/connector.
- Activate the switch to remove contact pressure, then pull out the normally closed contact/connector.
The contacts set downwardly should look something like this:
- Make clean each contact surface with your preferred cleaner[2] and method. The wiper contacts may stay in the switch and be cleaned there:
Reassemble the Switch
Replace the contacts in the reverse order of removal (pace b and then step a), and so reassemble the cover. Rather than even thinking of re-riveting, i prefer to use a minor machine screw, lockwasher, and nut. U.Southward. #2 size or metric 2mm size hardware should work.
Test the Switch
Information technology would be a good idea to put your ohmmeter (or equivalent) on the switch and test each prepare of contacts before returning the switch to service, to ensure that the cleaning job was successful. Tap the switch: the resistance reading should change little, if at all. Wild jumping with or without tapping indicates more cleaning is needed. With the ohmmeter connected, very slowly and gradually move the actuation push button/lever/device: the resistance should be adequately consistent until the "click" (or silent switch throw, for some microswitches), although information technology is virtually guaranteed that there will be some measurable changes. Changes of more than a couple of ohms or any wild jumps indicate that more cleaning would exist beneficial. Be sure to test both NO and NC contact sets, when applicable.
Congratulations!
(Hopefully) You did information technology! Yous (may) accept successfully disassembled, cleaned, and reassembled a microswitch! Possibly best of all, now that you take done so, should you lot ever need to "go in" again, you take had practice… and the switch is now held together by 1 or more screws, not rivets!
[1] This phrase, which i may have fabricated up, refers to the stories i accept heard about the miracles Cuban auto mechanics perform remaking unavailable (to them at least) parts for the many 1950s American cars there. It is meant with the utmost respect for these astonishing abilities to arrive and repair devices non originally intended to exist repaired (in most cases).
[2] Decades of feel have led me to prefer Caig Laboratories products over others, to the point where i have a page discussing Caig products.
Source: https://siber-sonic.com/electronics/microswitchrep.html
Posted by: richardsondrance.blogspot.com
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