junkhound
Senior Member
- Location
- Renton, WA
- Occupation
- EE, power electronics specialty
imo filing is not abrasive or chemical....? Sandpaper leaves grit so would be a no. How about wire brush, stainless of course only.
Does 110.14 prohibit filing contactor or relay points?
- Thread starter junkhound
- Start date
- Status
mtnelect
HVAC & Electrical Contractor
- Location
- Southern California
- Occupation
- Contractor, C10 & C20 - Semi Retired
The term I always use is "Burnishing", don't use sandpaper or a file. Use a tool that has replacement elements, that is designed for this.
ptonsparky
Tom
- Occupation
- EC - retired
IMO, if they look bad, replace them. Removing the silver from the contacts certainly will not help.
- Occupation
- Licensed Electrician
I use a sapphire nail file.
mtnelect
HVAC & Electrical Contractor
- Location
- Southern California
- Occupation
- Contractor, C10 & C20 - Semi Retired
I agree, if they are more than 10 years old, replace them.
mtnelect
HVAC & Electrical Contractor
- Location
- Southern California
- Occupation
- Contractor, C10 & C20 - Semi Retired
It's called "Preventive Maintenance". This is what we do with our "Maintenance Contracts". We routinely replace contactors in condensing units every 10 years, Condenser fan motors every 10 years, Combination capacitors every 2 years. We want to be "Pro Active". By doing this preventive maintenance it saves the customer and us from going out in the hottest and coolest days of the year.
mtnelect
HVAC & Electrical Contractor
- Location
- Southern California
- Occupation
- Contractor, C10 & C20 - Semi Retired
We are here sitting ... All this summer, not one of our Maintenance Contract customers have called us for any failure of their system.
Absolutely, but sometimes, dressing up the contacts can buy you some time to procure a replacement.
Joethemechanic
Senior Member
- Location
- Hazleton Pa
- Occupation
- Electro-Mechanical Technician. Industrial machinery
From working with my uncles doing automotive electric I remember they told me never to use emery cloth on commutators or ignition points. The reason was that the emery abrasive would embed in the surface and cause arcing. We always cut commutators on the lathe, and properly undercut the mica. Ignition points were filed.
And don't forget to test the armatures with the growler
And don't forget to test the armatures with the growler
ptonsparky
Tom
- Occupation
- EC - retired
I have moved half of each pair of contacts to a new position, or turned them 180. Sometimes it works for a while. Depended on the customer and how bad they needed it running. No warranty. Not even a taillight one.
rambojoe
Senior Member
- Location
- phoenix az
- Occupation
- Wireman
You however could pry up the wire terminal at the solder joint on the commutator to get more life out of the worn out carbon block, from motorcycles to power tools...From working with my uncles doing automotive electric I remember they told me never to use emery cloth on commutators or ignition points. The reason was that the emery abrasive would embed in the surface and cause arcing. We always cut commutators on the lathe, and properly undercut the mica. Ignition points were filed.
And don't forget to test the armatures with the growler
Joethemechanic
Senior Member
- Location
- Hazleton Pa
- Occupation
- Electro-Mechanical Technician. Industrial machinery
Lots of starters would get overheated and throw the solder out of the "hairpins". Some were worth resoldering, some it was cheaper to replace the whole armature, if you took into account the time involved
zbang
Senior Member
- Location
- Roughly 5346 miles from Earls Court
Hmm....
Filing does abrade the contacts in that it removes material.
Emery was prohibited as the dust is conductive, as I understand other sandpapers are not. That said, I'd never use anything courser than 800 on contacts, and only sparingly.
Filing does abrade the contacts in that it removes material.
Emery was prohibited as the dust is conductive, as I understand other sandpapers are not. That said, I'd never use anything courser than 800 on contacts, and only sparingly.
Joethemechanic
Senior Member
- Location
- Hazleton Pa
- Occupation
- Electro-Mechanical Technician. Industrial machinery
Yeah that was my understanding at the time also. Now there are so many different abrasives that I'm unsure. We used to do work for a copper smelter. There was a company that made abrasives out of thne slag from the smelting process. I know for a fact that that slag was conductive, Dust from the stuff caused all kinds of problems with anything electrical. It used to build up on the top of the batteries of the equipment that worked on the slag piles and discharge them overnight.
It was a really great abrasive, It worked it's way into all kinds of mechanical components and tore them up also. Now the whole place is a superfun site
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
In particular, if the contact surfaces have pits and ridges from arcing, there is often totally insufficient contact area to carry the load current. Smoothing the contact surface, even if the coating is removed, will buy you some (short) time.
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