Need help from the motor gurus

[Matt Day]

The motor on my Jet 15” 4-post planer stopped working. Was working one minute, then it didn’t turn on. No smells, Magic smoke or anything. I replaced the capacitor to no avail. Could it be the switch?

heres a video:
https://youtu.be/6FGsd-BrlcA

and the motor tag is attached too.

Any help would be greatly appreciated as I’m in the middle of a commission.

Thanks

[Mike Henderson]

Couple of things to try - and you may have done some of them.

First, get a meter and turn power on to the motor and check the voltage on the two wires that are the "line" to the motor (where the wiring goes into the motor - take the plate off and measure at the connections of that wire). If you're not getting voltage, then your off-on switch may be bad. If you have power, go to step 2

Step 2: You might have a problem with the centrifugal switch. To test for that, take the load off the motor (remove the drive belts) then power the motor and spin the shaft (either way). If it starts, you probably have a problem with your centrifugal switch since you already changed the start capacitor. Take the motor apart and clean the centrifugal switch.

If you have power to the motor and it won't start by spinning it, you probably have something open in the motor circuit (inside the motor). Check all the wiring and connections and see if you can find anything loose.

If not, check for continuity across the field of the motor. If you don't have continuity, you have a break in the field wires (very uncommon). If you have continuity, I can't offer any other solutions. Maybe someone else will have some ideas.

Mike

[DAVID DEWINTER]

How comfortable/knowledgeable are you around live circuits? Not knowing this, I'd recommend tripping the circuit breaker and check all the terminal connections from your power panel to the motor. You may just have a loose connection somewhere.

[Mike Henderson]

Yes, David points out an important thing. Make sure you have power at the outlet.

I often forget that very important step.

Mike

[Bill Dufour]

Unplug the saw and check to see if there is power at the outlet. Easy to do if it 120. If it is 240 you need something nearby with the same plug on it or a meter. After that follow what the others have said already.
Bill D

[Ed Edwards]

A couple of important points.
When checking for voltage, at the C/B, the receptacle, or at the motor connections, you'll want the circuit HOT.
BUT, when checking for CONTINUITY, make sure you pull the plug.

Ed

[Matt Day]

Thanks guys. There is power - if you watch the video you can see the motor clicks on for a second but doesn’t turn over. I’ll dig into the other suggestions this morning, starting with blowing out the motor and switch. I’d really like to avoid removing the motor, as it’s really tucked in there inside the cabinet. But of course I will if I have too.

Thanks!

[Malcolm McLeod]

... There is power - ...

Always a good idea to check voltage with a meter, even if a $15.00 HF or equal. (Think about a car battery on it's last legs - the starter engages, but engine won't turn over - it's the voltage not the connection.) There may be power at your motor, just not enough...? That said, the other replies are sound advice - and assuming you do have correct voltage at the motor - sounds like the motor may need surgery.

I was taught to look at electrical problems using 'law of halves': check the middle of a circuit for correct power; if it's OK, then the issue is in the downstream 'half'; so check in the middle of that half ... repeat until you isolate the issue.

[John C Cox]

Check that the motor is not stuck. Can you spin it freely?


If you have verified:
Spins freely/not stuck
Capacitor good
Has electricity


Then as a practical matter - the motor is dead. The problem is "inside" the motor.


Perhaps a motor rebuilder could get it going.... Usually that money is better spent on a new replacement motor.

[Matt Day]

Not exactly John, the magnetic switch is also a possible problem.

I eliminated the motor as the problem - I bypassed the switch and put a plug directly on the motor, spun right up when plugged in.


What can I check on the mag starter? I blew it out with air and it didn’t do anything. Also note, that holding the on button doesn’t change anything - in my brief research I found some people saying the machine stays on if it’s manually held down.

[Larry Komroff]

Is the reset button popped out? did you try and press it? It also looks like that starter is for a 5HP motor. If you look at the current rating on the overload switch it is set for 22Amps where your motor draws 14Amps max.

Larry

[Malcolm McLeod]

If you have a meter, set it for continuity/resistance (ohms), unplug the planer, and put the meter test leads on #1 and #2 lugs. Then manually engage the starter (Press the 'H' under the "JDE" label). The meter should read at or near 0 ohms (certainly less than 8-10ohms).

Repeat this for #5 / #6 lugs.

If either shows high resistance, you can move the associated wires to the unused L2 pole (#3 / #4 lugs). If both the L1 & L3 poles are reading high you can: 1. disassemble and try to gently file the crud off; 2. get a re-build kit for your contactor and replace the contacts; or, 3. get a new contactor.

...my best guess.

[Dan Friedrichs]

Ok, so it's the starter, not the motor.

And when you press and hold the button, it doesn't turn the motor on.

So: just double-triple check that you have 240V on the black and white wires at the top of the contactor. If so, check the voltage on those 2 brass bars between the contactor and the overload (the "top piece" and the "bottom piece"). The voltage between those brass bars should go to the input voltage when you press the black button in.

If you have voltage on those, but not on the red/black wires going to the motor, then your problem is with the overload. As Larry said, is it tripped? Press the red reset button.

If you don't have voltage on those brass bars, you've got some contacts in the contactor that are fried.

[Matt Day]

Great, thanks for the advice guys. I’ll do some testing later this afternoon.

I noticed on the bottom left of the contractor sticker that there appears to be a brown burn type mark.

I’ll report back.

[Dan Friedrichs]

Oh, one other thing - by "on button", are you referring to the little square black button? That button applies voltage to the contactor coil - essentially an electromagnet that pulls the main contacts closed. The "H-shaped" button (that Malcolm mentions) is attached directly to the main contacts, and can be pressed to manually close the main contacts (without the use of the coil).

So: if you press the little black button and nothing happens, you could have a failure of the coil, or of the contacts.
If you press the big "H" button and nothing happens, your problem is certainly with the contacts.

[Bill Dufour]

If you have to take the motor off do yourself a favor and cut the cord. Then add a male and female end to the two sections. This will make testing and removal much easier next time. You may want to cut it short on the motor. It will be easy to add a new short whip and male cord end onto the motor if you have take it to the workbench anyway.
Bill

[Matt Day]

Okay, I’m back after I erroneously got banned!

First thing, I finally realized the “H” shaped button existed!

So, I’ve got voltage at the line in, between the contactor and thermal overload, and terminal side. I also plugged in the motor directly to the wall and it ran it for 20 seconds or so, to make sure it was truly running properly. Check.

What next?

Because of the timing of delivery with Amazon, I went ahead and ordered a new starter. If the starter is dead, which I can only assume it is, I wanted the starter ASAP so I can get back to work.
https://www.amazon.com/gp/aw/d/B002LVUWHM

[Dan Friedrichs]

So when you press either the little black button or the H button, you get voltage at those brass bars between the contactor and the overload? But not on the output of the overload?

If so, then the overload is the problem.

Just to double-check, you tried pressing the red "reset" button on the overload and nothing happens?

If so, the overload is bad. The starter you bought on Amazon will be a good replacement for the entire starter.

Edit to add: is something broken on the overload? It looks like maybe the plastic case above the reset button is broken / loose / missing a tab?

[Matt Day]

A discovery!

I verified that I do have voltage through the switch to the motor leads. While testing and playing with the starter a bit, I realized that if I push the “H” button in hard and hold it, the motor spins up to full speed. I was just pushing it enough to engage the button to stay down, which gave me a split second of power. I thought that was it, but pushing it and holding it I suppose completes the circuit completely for the motor to fully turn on.

The small black button (non-“H”) doesn’t do this. I can push it quite firmly with no effect.

What I think is happening is the on button (small black button) isn’t engaging the “H” button (reset button?) fully. Is there anything to do about this? Blow it out some more? Possible corrosion?

[Dan Friedrichs]

Ah, a good discovery, indeed.

So your overload is fine, and the mechanical bits of your contactor are fine. When you press and hold the "H", you are manually closing the contacts that bring power to the motor.

The little black switch is supposed to temporarily energize the coil (the electromagnet) which pulls the contacts closed. If your starter were working properly, when you press the little black button, you'd see the "H" get "pulled" down by the coil (electromagnet). That's what's broken, here - either the coil, itself, or the little black button.

1) Disconnect power and use an ohmmeter to make sure the little black button is working as a momentary button should

2) If so, reconnect power and check that you're getting voltage to the coil when you press the button. I can't see the coil contacts in your picture of the starter - there should be two screws somewhere near the contactor side labeled something like "A"/"B" or "A1"/"A2", etc. If you can find both of them, measure the voltage between them when you press the little black button - should be 240V. If so, then your coil is bad (replace the contactor), if not, then you've got a problem with the wiring to the little black button.

As you dig into this, it gets a little confusing: the little black button momentarily energizes the coil, then a 4th switch pole on the main contactor "takes over" and supplies voltage to the coil once you release the button. This is why a motor starter will keep a motor off if the power blinks - an interruption in power causes the coil to release the main contactor, and since the 4th switch pole on the contactor was supplying voltage to the coil, once the contactor opens, it won't re-close until you press that momentary button. So those 4 screws to the left of the button are associated with that 4th contactor pole.

378062

[Malcolm McLeod]

Another way to describe this is that the little black button is part of the 'start' circuit to the coil, and the 4th switch pole is part of the 'holding' (or latch) circuit.

The O/L contact presumably is part of and feeds power to both, so it could also be the source of the problem...? (This is the #2 green bubble Dan has added.)

[Don Jarvie]

This is kind of after the fact since you ordered a new starter but if the motor itself has a reset switch you can dump the starter and use a switch for 20 amp. The starter is great but the overload protection is more important if the motor has no overload protection.

[Bill Dufour]

Do you have any remote stop or start buttons? it sounds like a bad stop switch somewhere.
Bill D

[Matt Day]

Dan - I have continuity across the start button.
The terminal you marked is blank. The one next to it goes up top left to L11, along with Line in.
None of the wires have changed and it’s been working for me for 5 years or more, and however many years before that for the previous owner.
When I press the small black start button the H button does pull close as it should, just not enough for some reason.


Bill - no remote buttons.

[Dan Friedrichs]

Hmmm...

So that sounds like a coil problem - it's not generating enough "pull" to fully engage the contacts. That's possible if the coil partially shorted itself, for instance - so while not a "common" fault, certainly a believable one that has some logical basis.

That black wire you mentioned...I had assumed it was to power the coil, as the coil power is usually ran through the overcurrent device at the location I drew the green line. I'm confused what that black wire does, then. In the Amazon link you posted, the last picture they show is a pretty good diagram of what yours should look like. In their picture, the coil is "A" and "B", and you can see how a wire comes down from the line input (in the upper left - just like yours), down to the overcurrent device ("98"), then from the overcurrent device to one side of the coil ("A").

Can you locate any similar-looking coil connections?

(Although at this point it's mostly academic - sounds like you'll be replacing the whole starter)

[Bill Dufour]

Not unkown for the armature to be rusted or gummed up with sawdust. If you can remove the armature from the coil clean it and the inside of the coil with compressed air and degreaser if it looks/feels gummy. If rusted it may need wire brush or sandpaper.
Are the contacts worn and need replacing re shaping?
Bill D.

[Malcolm McLeod]

Dan - I have continuity across the start button.
The terminal you marked is blank. ....

Matt, it's tough to be sure from a photo, but it looks like the #1 (red) note that Dan added to the pic points to terminals with no wire on them, BUT they do look to have a conductor 'strap' - running to the holding contact (L4). As per Dan, it may be academic, but just one more thing to be aware of...

Dan's advice seems thorough and more timely than mine, so I am going radio-silent to avoid confusion and will just follow along.

[Matt Day]

Just an update, but the new starter was essentially the exact same one I had, just brand new and working. Fit right up, wired, and works as it should.

I’m going to assume a bad coil with the old one. Wonder if it’s worth it to try and find a replacement coil/contactor? My feeble google searches haven’t found one, but I’m not exactly sure the part.

[John C Cox]

Probably not worth your time... The old one probably made it the better of 20 years.... Do you have a good reason to keep a weird spare laying around that long for another go around?