Delta Unisaw Just Quit

[novasail]

I've got a 1995 Delta Unisaw 36-825. I was doing a crosscut yesterday and the motor stopped mid-cut. There is power at the outlet. I discovered that the dust extraction hose had gotten clogged by a few thin cutoffs. There was a lot of built up dust inside the cabinet and dust had coated parts of the motor. I vacuumed all the dust out of the cabinet and, brushed and vacuumed off all the dust on the motor I could find. The motor did not feel hot to the touch.

I'm new at troubleshooting electrical components. Any help or suggestions are greatly appreciated. Thanks!

 

[Bill Clemmons]

Some motors have a "reset" button. Don't know if that saw does or not. If so, it's probably either red or black. Push it in until you hear a "click" and see if that makes a difference. When a motor stops suddenly like that it's usually an indication there was a fault of some type.

 

[novasail]

Bill, I've just searched all over the motor. Couldn't find a Reset button.

I again went through the paperwork I got with the saw when I bought it several years ago from its original owner. It turns out I could be wrong about the date of the saw. The Instruction Manual bears the date: 8-1-95, but there is a Supplement Instruction Manual dated: 7-1-96 (for the unpacking and assembly of a LVC power switch) and another dated 7-22-96, labeled Model 36-900 Limited Edition New Yankee Workshop Unisaw. That one only seems to deal with listing some enhanced features (e.g. 52" Unifence, table board, chrome handwheels, and a personalized nameplate , etc), and with attaching the nameplate, which the original owner never did. Another is a parts list and instruction manual for attaching an Outfeed Table, dated: 11-17-04. I'm guessing the Outfeed Table was an add-on.

Unfortunately there is no paperwork covering the motor.

 

[pop-pop]

You didn’t mention verifying power at the receptacle where the saw is plugged in.
Here is a poor man’s line voltage tester:

An outdoor socket from your local big box and a really low wattage bulb. Wire tip treatment is optional such as tip plugs (shown) or solder. A low wattage lamp bulb has enough electrical resistance to allow checking for 220V (burns bright but doesn’t burn out instantly).

 

[novasail]

Pop-Pop, thanks, I verified there is power at the outlet using my voltmeter.

 

[bob vaughan]

Chances are that the Taiwan-made IEC starter has failed. I've seen this before on this starter. The contacts deteriorate from standard use. I'm not a fan of IEC starters.

The contacts shown above came from one of those IEC GP Enterprises starters. The contact on the bottom is a NEMA size 1 for comparison. Fortunately for single phase one set of contacts isn't used. I just swapped the contacts and cleaned up the second pair. I re-installed them and the customer was happy to have the saw in service again. I recommended that he replace that starter with a good one.

starter contact comparison. The NEMA 1 size is rated for 3 HP at 240 volts.

This Furnas ad says it better than I can.

 

[Michael Mathews]

PM sent. Give me a call!

 

[bob vaughan]

Here's what the 83-651 Marathon motor should look like inside.

 

[novasail]

Thanks, Bob. Where do I locate the starter(s)?

 

[bob vaughan]

My bad.
A motor starter is often called a switch.

With the machine unplugged, take off the switch cover. Inside is likely to look like this.
If so, there may be a workaround by changing the location of one of the wires that feed the motor.
I didn't get a photo of the insides of the GP Interprise starter. A photo of your starter's insides may be helpful.
Examining the starter is easy and should be explored first. If that isn't the source of the problem, then the motor is next.

I'm assuming that all the wires to the starter have been checked for continuity. A loose connection in the feed wires can cause a stoppage also.

 

[novasail]

This is the inside of the switch. All the wires I can readily access are secure. There are others I can't reach unless I disassemble some of the, uhh, stuff.

I did attempt to start the saw this morning. On the 1st try there was a "rumbling" noise, then the motor ran for about 2 seconds before shutting off. After confirming there were no loose parts inside the cabinet, I tried again. 2nd attempt, no "rumble", it again ran for 2 seconds and shut down.

 

[novasail]

2 more views of the switch/starter.

 

[bob vaughan]

Great photos. If continuity checks out, then the starter isn't the problem.
For technical clarity, the top block with the push bar is the contactor block. Below that is the overload block, the one with the gray and blue plastic. To the right in red is the momentary contact block that controls the electromagnet that slams the live contacts together and feeds power down through the overload block and off to the motor.

 

[novasail]

Thanks for the help Bob! With the bar depressed, there is a continuity tone among the L1/T1 and L3/T3 sets. There are no apparent wires at the L2/T2 sets and no continuity tone for any combination of probe points. With the bar not depressed, there is a continuity tone between the T1s and the same for the T3s. I'm new at this but I guess that is normal.

 

[bob vaughan]

Apparantly the feed wires are connected to the T1and T3 lines and T2 isn't used. For single phase, the starter needs only two of the three contact sets. If one set is burned up then the feed and output wires can be connected to the unused set. I've done that as a stopgap measure on several Chinese starters that had burned up contacts on one of the lines.

It sounds like the starter is working.
I'll often leave the cover off, plug in the saw, and push the bar in manually with a non conducting stick. If the bar sticks in, then the starter is working. Do this at your own risk, of course.

Electrical problems can be horrible until the solution is found. It isn't like a screaming bearing or dull blade.

The problem could be as simple as the contacts under the stop button are corroded or occluded with dust. Blow a little air around the green and orange buttons.

 

[mark2]

silly question but does the motor and arbor spin freely?

 

[bob vaughan]

Delta Unisaw motors are TEFC (Totally Enclosed Fan Cooled). At least that's the theory. In practice, that doesn't always work .
Electrical problems are like the carnival game, Whack-A-Mole. An idea pops up, gets dealt with, and another possibility pops up in its place. On and on.
Another possibility could be that the motor's centrifugal switch failed (self-destructed) and shreded the windings.

Below two TEFC Unisaw motors.

 

[novasail]

silly question but does the motor and arbor spin freely?

Mark2, not silly - yes they do.

 

[novasail]

My Lovely Bride and I are going to drive up to Table Rock this morning and do some hiking. I'll break out the compressor and blast the starter when we get back this afternoon. If that has no positive effect, I'll open the motor housing and take a gander inside...

 

[novasail]

I liberally sprayed the interior of the starter with plastic-safe electronics cleaner then thoroughly dried it with compressed air. Buttoned it back up and gave it a go. Ran for 30 seconds before I stopped it. 2nd go I let it run for 60 seconds before I shut it down. Looking good so far! I then opened up the motor housing to see what might be the condition, dust-wise, in there. Looks clean as a whistle.

I think I might need to repack the grease/lubricant at the end of the shaft. Looking sort of dried and caked. Any suggestion as to which lube I should use?