LumberJocks Woodworking Forum banner

Problems with table saw tripping circuit

11K views 86 replies 32 participants last post by  MrUnix 
#1 · (Edited by Moderator)
I just received a new Grizzly G0715P table saw and I'm having troubles running it. I've done the conversion to 110 from 220 by changing the jumpers, installing a new 20 amp breaker at the switch and swapping out the plug. Tried powering it up and it very consistantly pops the breaker in my panel. I can reset the breaker and get the saw to start but if I stop it, almost consistantly it starts the 2nd time but will pop the breaker again the 3rd time.

I've got 2 20 amp cirucits located about 2 feet directly below the panel and the same thing happens to both of them.

Some things to note:
- When it does start up and run, it seems to run okay
- There is nothing else located on either circuit
- The saw was delivered to me with some pretty significant damage to the box. There was no visible damage to the saw, but the driver said it was probably dropped several times (he said it fell over once on him as well). In the back of my mind I'm wondering if that could have caused jarred something loose
- When I can get the saw to start, I notice this odd squeaking sound when the motor starts up, as if it's not lubricated properly or something. While its running it sounds normal, and as the saw spins down it sounds normal too. The only time that there is the strange sound is when it actually manages to start up
- The breaker at the saw switch does not trip (or at least I don't have to depress the button the breaker)
- Both of the 20 amp circuits were installed by the same electrician so I suppose there could be a problem there, but he's quite good and I would be very surprised
- I run a Jet DC1100 very regularly on one of the circuits and I think it's tripped once in two years or so
- I've double and triple checked the jumpers in the motor junction box
- I've double and triple checked the wiring on the plug

Any ideas? I'm going to give Grizzly a call tomorrow, but I'm kind of at a loss as to what might be going on. Thanks to everyone in advance.
 
See less See more
#3 · (Edited by Moderator)
The first thing I did even before plugging it in was aligning the trunnion. Currently the blade is +/- 0.001 to the miter slot. The blade is also perpendicular to the table. When I try to spin the blade by hand (saw unplugged of course), it does feel smooth and I don't hear any noises, of course who knows what happens when the motor actually powers up.

My immediate thought is like you said ksSlim, something has been knocked out of whack and there's possibly something binding, however one thing I can't figure out is if that's the case, why does the breaker at the tool not trip before the breaker in the panel? Am I misunderstanding how that works?
 
#4 ·
The same thing has recently started happening on my 25-30 yr old grizzly table saw, but only when it's cold in my shop. Usually starts up the 2nd or 3rd time, unless it is really cold, then it won't start till I warm the motor up with a space heater some. I have had a little luck in fiddling with the centrifugal switch, but it's no silver bullet. My thought is that either the motor needs to be lubed or that it is somehow on it's way out. In your case, since it's new, I don't know if that would be a possibility.
 
#5 · (Edited by Moderator)
Are you sure the saw is wired correctly for 220? The Grizzly info states the saw comes pre-wired for 220V. I would double check the wiring. Also, is there a magnetic starter on the machine? Is the circuit a GFCI? Do you have access to a clamp on meter to see how many amps the saw is pulling at start up?

The "breaker" at the tool is a magnetic starter. If the machine is wired for 110V is will have heaters installed to protect it for 110, not 220V. The draw at 110V is 16amps, 8amps at 220. If you re-wired to 220 and did not change the heaters the mag starter will not trip out until it senses an overload exceeding 16 amps.
 
#6 ·
Call Grizzly tech support and ask them. I would try to get them to send you another motor.

Are you comfortable with electricity? If so, open up the receptacle and connect a volt meter between one of the hot lines (one should be black and other red) and the neutral (white) wire. What is the voltage? Now watch the meter and start the saw, does the voltage change (drop) as the saw attempts to start? Then try the other hot line.

A mechanical thing to try would be to remove the belt and see if it continues to happen. If it does try loosening all but one of the motor mount screws and see if it continues to happen.
 
#7 · (Edited by Moderator)
For whatever it's worth, here's a picture of the box as it arrived to me. I think UPS routed it through Afghanistan!

Shipping box Gas Wood Carton Box


I did rewire the saw for 110. Checked the plug, that looks right, the breaker at the swtich has been swapped with from the stock 10 amp to the Grizzly supplied 20 amp and the jumpers on the motor look correct (there's really not much to it). Unfortunatly, I don't have a clamp on meter so I don't think I can measure the amp draw during startup. I've got a decent multimeter, honestly I don't really know how to use it :)

@JesseTutt, when you say measure the voltage at the recepticle, are you talking about the voltage at the outlet (on the same circuit) or something on the machine? Also I think that's a good idea on the belt. There's no possibility of damaging the machine if I run it without the belt, right? I've read in a lot of places if I try to run my dust collector without the impeller, bad things can happen.

Gonna give Grizzly a call in a little bit to see what they say about all this.
 

Attachments

#8 ·
There should be no problem running a motor without a belt attached. I used to test electrical circuits in machinery destined to go into factories without the motor connected to anything and ran them for hours as I debugged PLCs (Programmable Logic Controllers).

I was thinking of the receptacle as where you plug the saw into the outlet on the wall. 120V is a three prong plug, 220V (single phase) would be a 4 prong plug (hot, hot, neutral, and ground) - although my Grizzle bandsaw called for a 3 prong 220V plug (hot, hot, and neutral). I was wondering if there was a massive voltage drop (from the 120V it should measure) as the motor starts. As the voltage drops the motor tries to compensate by drawing more current.
 
#9 ·
So I removed the belt, but the breaker in my panel still manages to tip. I got the saw to run once, and there's no squealing sound like I first mentioned so I suppose that was just the belt slipping. Tried to measure voltage when I started it up, but when the panel breaker does trip, it does so immediately, so can't really see any difference.
 
#10 ·
Boy, asking Grizzly CS to swap out a motor sounds much easier than swapping out an entire TS. Detail all of your testing and then call CS. They may have additional testing suggestions, or they might immediately swap out the motor.

I think you have done well troubleshooting this issue. Sometimes I find it more advantageous to start with a detailed email of what the issue is and what you have done troubleshooting. Never hurts to include that damaged freight image just for effect. ;-)

THEN, if they haven't called back in a couple days, you then call them and reference the email (think paper trail).

Good luck. I am convinced that Grizzly will make it right.
 
#12 · (Edited by Moderator)
I spoke to tech support with Grizzly and they gave me a couple things to try. I'd really rather not send this saw back because as I imagine it would be a huge hassle. I've also already got the trunnions aligned to the miter slot and I know there's no issue with this one when raising or lowering the blade. I really think the damage by UPS was superficial to the box, but who knows.

First, they suggested to direct wire the motor (ie bypass the switch) and use the breaker in the panel to start/stop the saw (does anyone have any suggestions on what type of wire to buy from Home Depot?). If it still trips after that, the guy seemed to think it may be the start capacitor or maybe something with the contact points in the motor itself. These are things that he said could easily be fixed or checked. As a last resort he did say we could also replace the motor if it came down to it (swapping out the saw was also an option down the road but I don't really want to do that either).

I suppose it is a little bit of a pain to have to go through these troubleshooting steps, but one thing I'm very impressed about so far is how easy Grizzly has been to talk to. They seem to know what they're talking about and they do really seem to care like they want to make it right. Assuming it is something minor that can be fixed, I can't really blame Grizzly for that since who knows where the problem may have occured. As long as I have a working saw by the end of this I'm happy. I suppose I'll ask them if they can give me anything for my inconvenience (maybe a zero clearance insert or something) - can't possibly hurt.

Also, thanks so much to everyone that has replied to help out. This really is a great community. I'll update as I get more info.
 
#14 ·
Haven't changed out the breaker in my box, although that has crossed my mind. I've had ones go bad before but in that case they would always stay tripped. I also tried two different circuits, same result. Both were installed at the same time so I suppose it is possible that they were from a bad batch, but it seems unlikely. It'll be on my list of things to try though.
 
#15 ·
Did you see this? From the Grizz site

NOTICE: 110V operation requires part #T23999 circuit breaker and wiring procedures that must be completed by an electrician or other qualified service personnel. See Owner's Manual for details.
 
#17 ·
what brand of breaker are you using when the electrician was here he told me some brands trip below the rated value and he told me to buy only square d box and breakers.I am also curious if you have the access to the breaker and to the shop why did you decide not to do the 220 upgrade to the shop.

I also think Medic Ken is on the right track as his idea seems to make since too. Trouble shooting is so much fun.

I also think my saw is on a 30 amp circuit and the compressor is on a 40 they a re 220 though
 
#18 · (Edited by Moderator)
Yup I already installed the T23999 breaker at the switch.

I bought some 12/3 wire from Home Depot tonight, needed to make an extension cord anyway. The Grizzly tech I spoke to said I should bypass the switch by wiring the motor directly to this cord. The wires leading to the saw motor at the switch have the standard spade connectors on them. I don't have anything to connect that to my new wire. I'd rather not cut those off because I don't have new spades to put back on when I'm done. Anyone have any idea how I can tie this into my new wire? My first thought is just to tie it together temporarily with electrical tape, but I dunno, that seems way wrong.

@thedude50 - I've got SquareD breakers in my panel. The reason I don't have a 220 is because when I first had these 2 20 amp circuits installed, there were 2 spots left and I didn't see myself getting any 220 machines. I don't plan on being in this little space much longer (only 1/2 of a 2 car garage) and I'm out of room for any more tools, so it didn't seem worth the cost to me to have someone install a couple of tandem breakers to make room for a 220, especially when this saw will run on either. If I had to do it all over agian, yeah I probably would have done it differently, but what's done is done.
 
#19 ·
I wonder if your wire is sufficient for this circuit. You 're running on 12/3? Can you experimentally substitute 10?

Electricity really isn't my area but I have the help of a guy who seems to have memorized the national code. Anyway, with my pal's help I'm getting together the material and gearing up to add a subpanel in the garage to run 220 on 40 amp circuits. The plan is to run 6 from the main panel to the sub, and then 10 from the sub to the 220 outlets.
 
#20 ·
I would do the change myself if the breaker panel is in the shop.

for your test a temp try wire nuts and then tape It will work fine my bet is on the start up cap ill bet it is pulling too many amps
 
#21 ·
Do you know how to check continuity with your meter? Check the motor to see if any of the legs are shorted together (e.g. for a 3-prong 110V plug check round prong to longest flat prong then round to shortest and flat to flat). If there is a short in the motor it is sometimes possible to find it this way. If something is shorted it will draw a lot of current and trip the breaker.
 
#22 ·
@fuigb - the 12/3 is for the outlet to the saw itself. According to the chart above the wire at HD, it's good for a 20 amp load. Not wanting to trust that alone, I checked other sources on the interwebs it seems fine too. As for whatever's in the wall between the breaker and the outlet? Dunno, but I'm sure it meets whatever's called for in the NEC - my electrician is a good guy.

@thedude50 - I thought long and hard about doing it myself. I've replaced an arc fault breaker in there that went bad before, so in theory I know my way around the panel, but that's the problem - in theory. My background is in structural / mechanical engineering and there's just some sort of mysticism about electricity that puts it out of my comfort zone. Spring, mass, damper? Makes sense. Capactitor, resistor, inductor? Que?

@jjmill1980 - Just checked continuity
At the wall plug, switch on:
- Hot-neutral: yes
- Hot-ground: no
- Neutral-ground: no
At the wall plug, switch off: all no
At the motor, before the switch:
- HN: yes
- HG: no
- NG: no
As I said earlier, I'm no electrician / electrical engineer, but it seems right to me.
 
#23 · (Edited by Moderator)
I think fuigb is on the right track. The starting current for a motor can be 3 to 5 times full load current. I don't know what size motor your saw has but say it's 2 hp. You could be pulling 50+ amps on start. Probably right on the edge for instantaneous tripping that 20 amp breaker. If it was me, I'd go with #10 wire and a 30 amp breaker.
 
#24 · (Edited by Moderator)
If you feel comfortable with it , check the capacitor.

Cylinder Gas Font Metal Titanium


1 Disconnect the power going to capacitor. Put on safety glasses and gloves.

2 Discharge the capacitor by placing a screwdriver on top of both terminals on the top of the capacitor. Hold the screwdriver by the insulated handle so you don't shock yourself.

3 Disconnect the capacitor from the appliance by using a screwdriver and pliers.

4 Place the positive (red) lead of the voltmeter onto the negative terminal of the capacitor. Do the same with the negative lead. Look for the needle of the voltmeter to go all the way to the right. If the meter is digital, it should say "out of range" or something similar.

5 Replace the capacitor if you do not yield these results.

Having said that , a 30 amp circuit might be all you need. And double check that nothing else is running on that 20 amp circuit. 16 amps is pretty close to the rating of that breaker.
 

Attachments

#25 ·
What are the FLA (full load amps) on the motor name plate? My guess is those Sq D breakers are the issue. They and Cutler Hammer are the only ones that actually trip when they are supposed to! The Griz web site says 2 hp, but we know what they do with HP these days;-( They don't give the FLA.
 
#26 ·
BTW, if the motor is really 2 hp it will have a FLA of about 20 amps on 120 V. My motor calculator says it takes up to a 50 amp breaker to start it. You may have to run it on 240 V.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top