Wiring Thread: This stupid safety device started alerting that there wasn't safety!

The Something Awful Forums > Discussion > Hobbies, Crafts, & Houses > Wiring Thread: This stupid safety device started alerting that there wasn't safety!

Meow Meow Meow: Nov 13, 2010

Im putting a subpanel in my garage and will need to run a #6 to my main panel (pictured). The garage is on the other side of the wall on the left, so it should be a pretty easy run. Do you guys have any advice on how to pull the cable without doing too much damage to my walls? I've shown the joist direction in black and the ceiling heights line up in this picture and the garage.

I guess Im wondering if Im better off attempting minimal holes in the drywall and it likely being a more pain in the rear end or cutting out bigger chunks that would give me work space but be slightly more annoying to patch? Please guide me.

# ¿ Nov 12, 2020 02:17

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# ¿ May 9, 2024 23:10

Meow Meow Meow: Nov 13, 2010

Kaiser Schnitzel posted:

Hi it's me again, still trying to fix this danged tablesaw. 5hp 3 phase 230v, momentary contact on/off switch, some sort of magnetic starter (I think). Some pics for reference:
Nameplate:

Controls box wiring diagram:

Inside of controls box:

The problem is this-it runs fine and then suddenly loses power, and won't turn back on again until a certain? amount of time has passed. I'd guess around a minute, but I haven't actually timed it to see if it is consistent. It seems to happen more quickly/frequently when I am turning the saw on and off frequently (which is usually). Called the electrician, he thought probably a relay of some sort was tripping, maybe malfunctioning or maybe because the motor is overheating, told me to get the motor checked out. I pulled the motor and took it to the motor shop a few weeks ago, they tested it, said electrically everything was fine but the bearings weren't great, maybe that could be causing overheating, so they replaced the bearings. He said the guy had dipped it before he could tell him not to (they usually do a full rebuild I guess), so apparently they also dipped it and painted it for free. Wire motor back up, it runs fine for 10 minutes with no load, reattach to machine, still runs fine with no problems. Problem solved !

Until the next time I use it, when it cuts off again. It seems like it stays off for longer than it did before, but I dunno. I call the electricians, they come, everything seems fine, drawing a completely normal amount of current and I can't reproduce the problem while they are there. Of course. I've been too busy to gently caress with it until today, when the problem happened again and I could do a little more learning and a little more digging.

As I understand it, I have a transformer in the top right of the controls box-that gets some juice from the lines in and turns it into low voltage DC that controls the contactor in the top left. The thing below it is an overload relay with some heaters? in it. (GE CR324C310A4 if that is at all useful to anyone)

I was able to observe the control panel when the saw would malfunction and shut off. This little thing (https://www.ebay.com/itm/224686528817) would move up and down when I press the on/off switch:

And when the saw cut itself off, the part would move just as if I had pushed the off button. After some amount of time, I could hear a small click which sounded like it was coming from the contactor box, and then I could turn the saw back on.

So, uh, what the heck is going on and where should I start with trying to replace these electrical bits? I don't think it is the overload relay because it has a reset button of its own that I have never had to press. If indeed the motor is fine the problem must be in the controls somewhere, right? Even if a relay was tripping, it would be because the relay itself was malfunctioning, not because the motor was overheating, right? Could the contactor just go bad? Why would it suddenly work again after it rests for a minute? Is that a simple enough thing to pull out and replace with a new one?

Basically how to troubleshoot motor control i know nothing about??? I'm glad to get the electricians back if I need to, but between them and the motor rebuild I've already spent close to $500 fixing an $800 saw, and if I can troubleshoot this myself I'd rather try that first.

It looks like your overload heaters are rated for 6A (C778A), but your motor is pushing 12A. You should swap out the heaters for C151B as indicated on the table, should fix your problems.

Just to confirm you're running the motor on 230v?

# ¿ Dec 28, 2021 02:06

Meow Meow Meow: Nov 13, 2010

Kaiser Schnitzel posted:

That actually in hindsight makes perfect sense because I remember the electrician who wired up the saw saying it had been wired for high voltage/460v and he rewired it for my 230v.

Yeah, so you've probably been getting lucky for awhile/not pushing the saw too hard, but now for whatever reason you're surpassing the 6A causing the overload to trip. Also makes sense it's that because they usually automatically reset once things cool down, just like you're describing. It's easy enough to overlook when wiring it up if you don't deal with motor control/motor circuits too much.

# ¿ Dec 28, 2021 02:18

Meow Meow Meow: Nov 13, 2010

Kaiser Schnitzel posted:

The only fuse I see is on the bottom of the transformer and it says 250v AC 1R 10KA 1-6/10 amp. Elsewhere on the fuse it says TRM 1(i?)-6/10. Is there somewhere else I should look for a fuse? Is the little S thing on the wiring diagram above �T1, T2, T3� a fuse?

It looks like your question about buying the heaters has been answered.

For the fuse, you should be checking upstream, ie. at your breaker panel or fuse panel. You want to make sure that it has the right size for when your motor was rewired to 240V from 460V, because once you swap your heaters out you might be tripping upstream at the panel instead if that's not the right size. The fuse you found is for your control circuit (the pushbuttons and whatnot) and should be fine.

The S looking things in the wiring diagram are your overload heaters.

# ¿ Dec 28, 2021 19:27

Meow Meow Meow: Nov 13, 2010

The breaker trip time is dependant on the current, so if you're just over, say 16A, it could take a minute or even longer before the breaker actually trips. The higher overcurrent the quicker it will respond. This is to minimize nuisance trips for things like motor inrush, etc. But yeah, don't exceed 80% continuous.

# ¿ Sep 9, 2022 15:04

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# ¿ May 9, 2024 23:10

Meow Meow Meow: Nov 13, 2010

I would simply remove the vent cover, notch the corners and file them smooth and run the ethernet across the floor through the vent (similar to how it is running behind the baseboard). You might not even need to notch the vent cover, in any case the notch would not be visible.

# ¿ Mar 11, 2024 19:50

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