Chamberlain opener repair

[rickpaulos]

During the super cold weather just before Christmas both my 22 year old Chamberlain "Whisper Drive" belt drive garage door openers were misbehaving. After I sprayed the door tracks and wheels with some lube, they did work better. Then a couple days later one failed. The main gear (plastic) was shredded. I ordered a replacement and put that in. While it was still on the bench I ran it with no load and sprayed the new gear to get it running smooth and quiet. After about 30 seconds the capacitor blew. New capacitor ordered.

What is the purpose of the capacitor and why would it blow now. Was it just age?

I don't see any polarity marks on the capacitor. Looks like an electrolytic but is it?

I like the quiet nature of the Chamberlain belt drives. They have worked just fine for 22 years. After taking the one apart for repair, I'm not impressed. Okay, far better than a Stanley I installed for a relative 20 years ago but it could be better. I looked at new models and they all are too high tech. (and double the price from 20 years ago) I don't want even more digital circuitry that is sure to fail soon and my guess is there is more plastic inside, not less. The previous Genie openers were worn out and really old (no) tech and hardly any plastic. I had to repair the chains on those several times (before the www made parts so easy to get).

 

[rickpaulos]

The oem capacitor.

 

[The Cobbler]

just the luck of the draw with the cap failing. AC voltage caps are not polarized, you can't wire them backwards

 

[walta]

What is the purpose of the capacitor and why would it blow now. Was it just age?

I don't see any polarity marks on the capacitor. Looks like an electrolytic but is it?

The short answer is the large capacitor is what allow your AC motor to work by shifting/ delaying the flow of current thru one of the motors two windings.

Why it failed at that moment is hard to say. Could a 22-year-old cap fail at any given moment, sure it could. Could the fact that you moved a 22-year-old cap make it fail, maybe. Seems likely the motor was overloaded while it was destroying is gears and drawing more current than normal and may have damaged the cap.

My wild guess is the door springs are out of adjustment forcing the motor to work harder than it should. I am also guessing you have sprayed goop on every moving part of the door. Some of the old goop has turned gummy and attracted dirt over time became less inclined to move when it got cold. I think your well meaning lubrication is the root cause of the gear and cap failures. I say clean all the lubricated parts inspect and replace the ones that are worn have the springs adjusted so the door almost pops half way open on its own.

The caps used in AC motors are bipolar so there is no positive or negative.

Walta

 

[Innovate1]

What walta said. Caps go bad over time.

Disconnect the opener from the door and check the balance. If you place it about 4 feet up it should stay there or have a very slight tendency to move up or down - no significant force to keep it in place. Likely over the years the springs have weakened some and need adjustment. If you don't fix that you are likely to break more stuff in the opener.

 

[sparky 1971]

You're far enough into it now that you might as well replace the cap, but it's a door opener and they fail. The drive gear stripped on mine a couple weeks before Christmas when the dog ran under the door while it was closing. The door stopped and reversed, but that's when the gear failed. It was between 18 and 20 years old so I just bought a new opener for around $200. The reversing sensors are now mounted on the ceiling about 8" apart to prevent future emergency direction changes and potential stripped gears.

 

[GreyOwl]

Hopefully you won’t end up with a smashed dog!

 

[rickpaulos]

The reversing sensors are now mounted on the ceiling about 8" apart to prevent future emergency direction changes and potential stripped gears.

Those light beams are great for collecting spider webs and leaves and preventing the door from closing. Mine are about 1/2" apart on the ceiling. This particular model has a rotation sensor at the back of the motor. If the door hits something and stops, it reverses. So the raccoons and possums won't get squished. No dead critters yet. The light beams are surely a cspc mandate and are probably a good idea if you have kids around and an opener with no speed sensor. No doubt some kid was crushed prompting the requirement.

New cap arrived this evening. I was thinking I will plug the motor into a amp meter and watch for excess draw before i reinstall it. Compare the amps with the label.

The door moves quite freely now. I did lube it this fall with a "100% Silicone" spray. Mistake. I think that is what gummed up the wheels and tracks when it got so cold. I've yet to find a use for that stuff but I have a couple cans yet to use up.

 

[Max]

The door moves quite freely now. I did lube it this fall with a "100% Silicone" spray. Mistake. I think that is what gummed up the wheels and tracks when it got so cold. I've yet to find a use for that stuff but I have a couple cans yet to use up.

Lithium grease for the garage door. I use silicone spray on my foosball table.

 

[nickelTwin]

Lithium grease for the garage door. I use silicone spray on my foosball table.

Don't use grease for rollers or track where the temperatures are cold.

 

[rickpaulos]

Opener still on the bench.

New capacitor installed.
No light bulbs installed.
Opener label says its rated at 5 amps.
Motor label says its 4.5 amps.
When off, the radio is drawing about 0.05 amps.
I ran the motor, not attached to the main gear, for about 10 seconds. Meter shows 5.5 to 6 amps draw. The capacitor got HOT in those 10 seconds. Almost too hot to handle. Perhaps the motor windings are toasted.

I measured the current draw on my matching garage door opener. My garage has 2 doors and I put in matching openers in 2000.
Second opener is drawing about 4.3 amps while operating, right to spec. About 0.29 amps when the radio and light are on. The second door doesn't get used nearly as much.

I found a Chamberlain belt drive model B2202 for $199 new (with the WIFI). IMO, more garbage to fail. Will the remotes for the current models work with the 2000 models? Chamberlain on-line tech says no so the s.o. will insist on replacing both so she only has to have 1 remote for both doors.

2 new openers and a keypad. $199 + $199 + 40 = $440 & tax.
New motors for about $180.
Used motor for $40 That would keep the remotes compatible and I won't have to change the tracks or wiring.

ref: Motor no 123C0159

 

[rickpaulos]

I took the motor apart. The windings look quite good. Resistance measures about 7 ohms. The felt packing around the sleeve bearings were completely dry. I put a lot of 3in1 Motor Oil in the felt and reassembled. There are no oil ports or grease pots like some motors have. Still drawing about 6 amps and the cap got hot after about 25 seconds.

The windings resistance measured about 7 ohms. Ohms law says 120vac at 6 amps should be 20 ohms. But with the many loops, there is also inductive resistance when 120 volts is flowing. The many close proximity magnetic fields add their own 'resistance'. That is called Impedance.

used motor ordered

 

[nadogail]

I will not own a Chamberlain garage door opener, they may be a good product but their local representative sold me one knowing that they suffer radio interference problems in my area.

 

[dscheidt]

Those light beams are great for collecting spider webs and leaves and preventing the door from closing. Mine are about 1/2" apart on the ceiling. This particular model has a rotation sensor at the back of the motor. If the door hits something and stops, it reverses. So the raccoons and possums won't get squished. No dead critters yet. The light beams are surely a cspc mandate and are probably a good idea if you have kids around and an opener with no speed sensor. No doubt some kid was crushed prompting the requirement.

Force sensing has been required for much longer than the electric eyes. But the limits on how much force can be applied are quite high, and are enough to cause serious damage to a car, or kill an adult.

 

[Almost Retired]

I took the motor apart. The windings look quite good. Resistance measures about 7 ohms. The felt packing around the sleeve bearings were completely dry. I put a lot of 3in1 Motor Oil in the felt and reassembled. There are no oil ports or grease pots like some motors have. Still drawing about 6 amps and the cap got hot after about 25 seconds.

The windings resistance measured about 7 ohms. Ohms law says 120vac at 6 amps should be 20 ohms. But with the many loops, there is also inductive resistance when 120 volts is flowing. The many close proximity magnetic fields add their own 'resistance'. That is called Impedance.

used motor ordered

there is a switch to disconnect the start cap as soon as the motor is up to speed. it will be either centrifugal, or electrical.
that is what is wrong. it is not disconnecting the start cap from the circuit
start caps are not designed or intended to remain in the circuit like metal cased run caps
you dont need a new motor, you need a new switch

if you continue to try to run the motor with a bad switch, the start cap can explode like a hand grenade
i strongly advise you not to find out

i agree with you oiling the bearings, but if you continue to lube external parts, then you need to check every few months to see if the lube has collected dirt etc or stiffened, most especially in cold weather

 

[walta]

there is a switch to disconnect the start cap as soon as the motor is up to speed. it will be either centrifugal, or electrical.

My guess is the opener motor is wired like the one in this diagram the cap is a run cap it has current flowing thru it whenever the motor has power applied.

If the reversing switch is in the A position the cap in in series with the aux winding and the motor runs counter clock wise.

If the reversing switch is in the B position the cap in in series with the main winding and the motor runs clock wise.

Walta

 

[walta]

I took the motor apart. The windings look quite good. Resistance measures about 7 ohms. The felt packing around the sleeve bearings were completely dry. I put a lot of 3in1 Motor Oil in the felt and reassembled. There are no oil ports or grease pots like some motors have. Still drawing about 6 amps and the cap got hot after about 25 seconds.

The windings resistance measured about 7 ohms. Ohms law says 120vac at 6 amps should be 20 ohms. But with the many loops, there is also inductive resistance when 120 volts is flowing. The many close proximity magnetic fields add their own 'resistance'. That is called Impedance.

You Ohms law formula is correct for a DC circuit but it gets a lot more complicated for AC circuits. In short you can’t measure impedance (AC resistance) with any meter you are likely to own.

I am wondering about the cap you bought is it a run or a start cap? Generally, run caps have metal cases and start caps have plastic cases.

If you are sure you have the correct cap try running the motor without a load by removing one if the gears.

Walta

 

[Almost Retired]

You Ohms law formula is correct for a DC circuit but it gets a lot more complicated for AC circuits. In short you can’t measure impedance (AC resistance) with any meter you are likely to own.

I am wondering about the cap you bought is it a run or a start cap? Generally, run caps have metal cases and start caps have plastic cases.

If you are sure you have the correct cap try running the motor without a load by removing one if the gears.

Walta

you are not paying attention to the pictures or statements he posted
post #2 shows an OEM start cap in the circuit
at the end of his statement you quoted,
he said
That is called Impedance.

 

[dogdog]

you are not paying attention to the pictures or statements he posted
post #2 shows an OEM start cap in the circuit
at the end of his statement you quoted,
he said
That is called Impedance.

what is impedance?

 

[Almost Retired]

what is impedance?

in an energized circuit it is the ac equivalent of dc resistance
when windings are involved (either a motor, relay coil, or transformer) the production of the magnetic field creates most of the impedance
there is also some created by other portions of the circuit

the point is that an ohms measurement with a battery powered meter will not show impedance
it will show dc resistance which will be lower than the impedance in an ac coil

the op took note of those points when he did an ohm measurement, then the math to arrive at dc amps
and as expected he saw that the FLA on the motor tag was different than his calculation

the primary purpose of making an ohm measurement in a motor or other ac circuit is to verify continuity