Brushes and switch question

[ohiovacuums]

I have a Model 72 Premier with motor made by the Electric Vacuum Cleaner Co.
It did not run when I got it so I disassembled it to inspect. First question: how do I test the on/off switch ? Picture #1 shows a continuity tester with one end on the positive end on plug and the other end as shown....is this not the way to test ?
Picture # 2 shows a broken brush. Where can I obtain new ones and how do you measure them ? If that size is not available can you buy larger ones and file them down to size ? or is that just a crazy idea ?
Thank You.

 

[zenith12]

You can

You can buy blocks of grafite off of Amazon cheep and make your own brushes with a hack saw and a file.

 

[kirboover]

Switch

Use continuity mode on a multimeter. Put one probe on input + and other on output +. If there is a beep when you flip the switch it is good. If there is no beep, there is something wrong with your switch.

Regards, Avery

 

[ohiovacuums]

Kirboover

Thank both of you for the replies...when you say put one end on input and other on output, do you mean on the switch wires ? I didn't want to cut those wires and have to put them back together if I could avoid it.

 

[human]

No, you would just need to put the leads where there is bare metal on both of the switch contacts. You want to keep the circuit small so you know you're testing only the switch. I prefer to use an old fashioned analog volt-ohm-milliammeter (VOM) because I'm just an old fashioned, analog kind of guy. Fortunately, that switch looks like pretty much of a commodity, hardware store part so it should be easy to replace

Just an observation. What I can see of the cord in that photo looks pretty sketchy. You probably should replace it.

 

[huskyvacs]

When testing why a motor doesn't work, always resort to probing last.

First and most common is the power cord has rotted or shorted together (you would know if it makes a dead short).

Next thing to check is the switch, the terminal plates in the switch can oxidize with wear and the passage of time and make a poor connection. The switch can be worked with electrical contact cleaner and manually flicking the switch about a dozen times back and worth and seeing if that gets it.

If the switch does not operate, disassemble and inspect the switch.If possible, use a piercing alligator clip lead on each wire and and bypass the switch and see if the motor turns on.

Failing all that, then open up the motor housing and inspect and probe if need be. A motor will never be completely dead and refuse to turn on unless it is the switch or the power cord. It will always make some kind of noise or something will happen. Most always you can directly see why a motor has not turned on, in your case the broken carbon brush. Those little ball switches are common to get dust and lint packed in them, so I would not atall be surprised if the switch is dirty too.

Good luck! Antique vacuum motors are not at all complicated to diagnose, pretty simple in how they operate. I've never really had to use a multimeter except on vacuums with circuit boards and other electronic faff in them. One little capacitor the size of a bean fails and knocks the entire vacuum out.

 

[kirbyklekter]

Carbon Pressure!

If you do end up making your own brushes you'll want a good fit in the holders. They need to fit just snug enough so that they don't rattle in the sleeves but not so tight that they could bind up and not stay on the armature as they wear.If you sand or file them,finish with a really fine grit paper and go with the direction of the armature on the tips (left/right) and you might need to use a stone to seat them further. Make sure the springs are doing their job too and equal pressure on both sides

Good time to clean up the space between the copper on the armature if needed and of course the all important bearings on both ends. Good luck,you've got this.

Billy

 

[madman]

There is no need to make your own brushes. They are commonly available. Measure the height x width x length. Get yourself some cheap digital calipers from Harbor Freight. It looks like 1/4" x 1/4" from the picture. Sellers may list in fractional or decimal. You probably could just measure with a tape or ruler. Length is not super critical, long ones can be filed down. Though I'd recommend finding a round object about the same diameter of the commutator, wrapping that in 150 grit, and sanding off any excess length so you keep the curvature. Also a criterion for the right brush is the connection type, in your case, a spring only, with no lead. Though if it had a lead and a spring it wouldn't matter much. Keep your old brushes, you may need to reuse the springs.

Go to mcmaster.com, search motor brushes. Find the appropriate ones there. They're not the cheapest, but I bet you they have them. Once you know the available sizes and pick one that matches yours best, you can look on ebay or amazon. You likely won't find it by part number as McMaster's are proprietary, but the common measurement will help. Then again, if you buy from McMaster, it probably won't be more than $15 or so. $7 if you're lucky on ebay.

 

[ohiovacuums]

Thank You !

Thanks for all the input. I bought a new switch at Lowes and ordered brushes from McMaster that are 3/16 X 3/16....mine measure 5/32 X 5/32 so (hopefully) I can file down slightly. Billy---thanks for the encouragement but I think you have more faith in my abilities than I do. I'll follow up with a picture of the finished WORKING vacuum.

 

[human]

Yeah, not everyone is a machinist, myself included. It's good that you recognize your limitations and work within them. That's better than getting in over your head. Good luck with your project.

 

[madman]

5/32" is awfully specific. There's a good possibility they are actually 3/16" nominal, you may not have to modify them at all.

 

[hoover300]

Please do! This a very rare vac and I've only seen one nicer example so far(youtube).

 

[ohiovacuums]

It runs !

I've been busy at work but, thanks to all of your input, got it running.
The original cord is fine..I may put it back on someday.
I removed the original switch and cut the wires too close to the switch because I
wanted enough extra wire just in case. I then determined the switch was OK.
I did put in new brushes...had to file them a little and try to curve the edge to
match the armature. I did have the motor housing pretty well polished but I disassembled and re-assembled three times for various reasons and it doesn't shine like it did. I do have more questions.....does anyone know what the long handle looks like ? It must have had a long handle so that you could vacuum the floor while standing up. Also, the base plate has some rust that I could remove a little more but I'm sure having it re-chromed would be expensive...any ideas on making it a little better looking ?
I attached some pics.