Overload protection for Rigid 4512

[Alfred Hess]

Does anybody know if this saw has overload protection. I am blowing a 20 amp breaker occasional ripping 2x4s at 110 volts. I would like to switch to 220v but the circuit has a 30 amp breaker and I afraid I will cook the motor if the saw stalls. Any ideas would be greatly appreciated

[Art Mann]

The motor will almost certainly have thermal overload protection. My Ridgid table saw (model 3650) had a red reset button you had to push to get it working again. I am just wondering why you are having breaker reset problems with the setup you have now. According to what I read, the full load current is only 13A. Maybe you are using the wrong blade, which loads the saw too much. Are you using a 40 tooth all purpose blade or worse, an 80 tooth crosscut blade? If so, switch to a 24 tooth thin kerf rip blade. The saw will perform like you doubled the power if that is the case. Of course, it is possible that the breaker has gotten weak.

[Alfred Hess]

Thanks Art. I think that is a good tip about the blade. I don't currently have a thin kerf and am using a combination blade. But I plan to buy one. However I am thinking about adding a 220 volt circuit anyway because I don't have enough power in my shop. The 30 amp circuit is the one that is readily available. And I can also use it to put a heater in the shop. I am wondering if the saw has overload protection why it is blowing a 20 amp slow blow breaker. I can't seem to find any kind of reset switch on the saw.

[Rod Sheridan]

Innexpensive breakers have thermal overload and magnetic trip functions.

Mag trip is for short circuits when currents are around 7 times breaker rating or higher and is almost instantaneous.

Thermal trip has an inverse curve and protects against long or medium term overloads between about 125% and magnetic trip territory.

The thermal mass of the breaker is small, the motor thermal mass is high.

The breaker will trip at a small overload say 200% much faster than the motor overload due to the motor thermal mass.

That's why you need thermal overload protection for motors.

The other issues are the blade, the material and the machine.

Dimensional lumber is often not dry and has a lot of internal stress, you should be using a splitter and guard, a short rip fence, and a full kerf rip blade of 24 teeth type.
Regards, Rod.

[Alfred Hess]

Thanks Ron for your very detailed reply. So I guess the r4512 has some thermal protection somewhere I can't see? Is this typically non destructive ie turns the machine back on when it cools down. Or would I have to replace some component in the motor? Do you think I am safe to switch to a 220v 30 amp circuit if I change the wiring of the saw to 220V?

[Art Mann]

I have stalled the motor on my Ridgid 3650 on more than one occasion. The thermal overload tripped just as you would expect. I am sure the same thing would happen if you rewired your saw for 240V. That still leaves the question of why your saw is drawing too much current. You need to stay after that problem as well.

[Alfred Hess]

I have stalled the motor on my Ridgid 3650 on more than one occasion. The thermal overload tripped just as you would expect. I am sure the same thing would happen if you rewired your saw for 240V. That still leaves the question of why your saw is drawing too much current. You need to stay after that problem as well.

So what happens on the 3650. Do you wait for awhile and the saw comes back on ? Or do you press a button of some sort? Thanks Alfred

[Art Mann]

As far as I can remember, I had to press the reset button to get the saw operational again. My guess is you will have to let the motor cool down and then cycle power to get your saw going again. It would not be good if the motor started turning unexpectedly after an arbitrary cool down period.

[Robert Engel]

You are damaging your machine. Thermal protection or not, constant overheating will weaken and shorten the life of the motor.

Especially when working with construction lumber, there are other things to consider (besides lack of power in this type saw):

Straight or jointed edge against fence?

Twisted board?

Using a thin kerf blade? Sharp blade? Ripping (not combo) blade? Feed rate?

Lumber wet?

Knots or internal stresses in boards?

If you are seeing any burning on the lumber any one of the above might be the cause of your issues.

[Rod Sheridan]

Yes, it's safe to go to 240 volts however you have to solve your problem first. The saw should run fine on 120 volts.

1) put a 24 tooth standard kerf rip blade on it.

2) attach a piece of ply or MDF so that the fence ends just past the beginning of the blade when ripping solid wood


3) make sure you're using your riving knife and guard.

That should solve your problems.

Are you using an extension cord? Anything else on that circuit?

Regards, Rod.

[Alfred Hess]

Yes that sure makes sense. The saw can't just arbitrarily start again and I can't find any button. Which makes me suspect that the R4512 does not have a way to reset after a thermal failure. I appreciate all of the suggestions about improving the my ripping technique and I will implement many of them.

However I still have a nagging doubt that if I switch to 220 in order to free up the 110 circuit in my shop and some unforeseen motor stall occurs I will damage the saw motor. Right now I have the protection of a 20 amp fuse. I don't know if a 30 amp fuse at 220 will blow before the motor is toasted.

Do you think there is someone at Rigid who knows about overload protection on the saw?

[Tony Shea]

I would just buy a 2-pole 20A breaker and replace the available 30Amp breaker. Then re-wire your saw to 220V which I've done to my saw, the same exact model you have. But as others have stated I would highly recommend using a thin kerf 24 tooth blade. If not thin kerf then certainly get a 24T ripping blade for the task at hand. I love my Frued 24T ripping blades, which are not thin kerf and I've never had an issue with bogging down using the same exact saw.

I highly recommend NOT just wiring your saw off of the 30A breaker though. It will certainly work and yes the motor is protected by thermals that are not resettable, but I do not recommend banking on those thermals for protection of your motor and most importantly the WIRE!! The wire inside the motor is not rated at that current and I assume the wire going to the saw would not be rated, but without knowing the details of it that is just a guess. Buy a $10 2 pole 20A breaker and be done with it.

[Dave Sabo]

My thoughts echo some of the advice you've already gotten.

That saw should have little trouble ripping dry 2x4s if properly tuned. As suggested - dbl check the blade to fence alignment. Not yet suggested, check to see that the drive belt is tight. You might be surprised that it's loose or that it could make a difference. I once used a 3hp. saw that struggled with 3/4" material and a premium blade. Loose belt was the culprit.

Contrary to conventional wisdom, the panel breaker is not there to protect your motor. It's there to protect the wiring attached to it. It's been mentioned to check / change the breaker. You should also check to see of the screws are tight that clamp the wire as well as checking to see that hte connections are secure on the saw and motor too. Tougher to check are the windings on the motor and the feed wire itself from the breaker to the shop for continuity and partial breaks.


However I still have a nagging doubt that if I switch to 220 in order to free up the 110 circuit in my shop and some unforeseen motor stall occurs I will damage the saw motor. Right now I have the protection of a 20 amp fuse. I don't know if a 30 amp fuse at 220 will blow before the motor is toasted.

You are focused on the wrong issue here. You shouldn't really be worried about the motor, but your house.

[Andy D Jones]

The breaker is responsible for protecting the fixed wiring and outlet from causing a fire. A plugged in appliance is responsible for protecting itself (including its cord) from causing a fire or unsafe condition.

This does not mean the appliance is responsible for making sure it can be used again (e.g. with a not-easily-replaceable fuse vs a self-resetting or manually reset protection system. Some cheap self-resetting systems (e.g. PTCs) will "trip" at lower currents the more times they are tripped.

Convertible induction motors have two windings. When configured for 110V, the windings are in parallel. When configured for 220V, they are wired in series. So either way, they each see the same current.

-- Andy - Arlington TX

[Alfred Hess]

My thoughts echo some of the advice you've already gotten.

That saw should have little trouble ripping dry 2x4s if properly tuned. As suggested - dbl check the blade to fence alignment. Not yet suggested, check to see that the drive belt is tight. You might be surprised that it's loose or that it could make a difference. I once used a 3hp. saw that struggled with 3/4" material and a premium blade. Loose belt was the culprit.

Contrary to conventional wisdom, the panel breaker is not there to protect your motor. It's there to protect the wiring attached to it. It's been mentioned to check / change the breaker. You should also check to see of the screws are tight that clamp the wire as well as checking to see that hte connections are secure on the saw and motor too. Tougher to check are the windings on the motor and the feed wire itself from the breaker to the shop for continuity and partial breaks.


You are focused on the wrong issue here. You shouldn't really be worried about the motor, but your house.

So you are saying if the saw fails and I don´t have 30 amp wiring all the way to the saw this wire in the wall could catch fire_

[Alfred Hess]

Yes, it's safe to go to 240 volts however you have to solve your problem first. The saw should run fine on 120 volts.

1) put a 24 tooth standard kerf rip blade on it.

2) attach a piece of ply or MDF so that the fence ends just past the beginning of the blade when ripping solid wood


3) make sure you're using your riving knife and guard.

That should solve your problems.

Are you using an extension cord? Anything else on that circuit?

Regards, Rod.

So I guess the idea of the short fence is to prevent the wood from squeezing the blade when it closes in on itself due to internal stresses?
Can this still be done with the riving knife in place?

I am using a short extension cord.

Thanks
Alfred

[Alfred Hess]

I am going to try to use the same circuit as my kitchen stove which is just behind the garage wall. Which means I have to keep the 30A breaker in place. It would be nice if I could get some kind of combination magnetic breaker starter for my saw.

[Lee Schierer]

My son has the same saw on a 20 amp breaker with no problems. I would suggest you check a couple of things.

1. If your saw is connected by an extension cord not counting the cord that came wit it, what is the wire size of the extension cord and how long is it.

2. You said it trips when ripping, are you using a dedicated tip blade?

3. Is the wood being ripped relatively straight?

4. Is your blade sharp and clean?

5. Is there anything else on the circuit being used by the saw that is working at the same time?

6. How far from the breaker is the receptacle being used for the saw.

[Art Mann]

Yes that sure makes sense. The saw can't just arbitrarily start again and I can't find any button. Which makes me suspect that the R4512 does not have a way to reset after a thermal failure. I appreciate all of the suggestions about improving the my ripping technique and I will implement many of them.

However I still have a nagging doubt that if I switch to 220 in order to free up the 110 circuit in my shop and some unforeseen motor stall occurs I will damage the saw motor. Right now I have the protection of a 20 amp fuse. I don't know if a 30 amp fuse at 220 will blow before the motor is toasted.

Do you think there is someone at Rigid who knows about overload protection on the saw?

There is something you need to realize about household breakers. It has already been partially brought up by someone who correctly said that breakers are designed to protect the house wiring and will do nothing for what is plugged into them. The fact is breakers will typically sustain twice the rated current for around a minute and 10 times the rated current for a few seconds. They are designed this way to prevent nuisance trips during the surge of current at startup. Your saw will, in all probability, self destruct if you develop a stalled rotor long before the breaker trips, unless the motor thermal breaker trips. Replacing the 30A breaker with a 20A breaker will do almost nothing to help the situation. I am not a Ridgid employee but I am an electrical engineer with a lifetime of experience.

Replace the 20A breaker and see if that fixes the problem. Breakers do go bad from time to time. If that doesn't fix it, you have a problem with the saw that is not related to the power source and you need to solve it before doing anything else.

[Rod Sheridan]

So I guess the idea of the short fence is to prevent the wood from squeezing the blade when it closes in on itself due to internal stresses?
Can this still be done with the riving knife in place?

I am using a short extension cord.

Thanks
Alfred

You are correct Alfred, and yes you leave the riving knife in place.

The fence can't do anything except create problems after the wood has been cut if the wood moves. This is why multi-function fences come with many saws.........Rod.

[Lee Schierer]

So I guess the idea of the short fence is to prevent the wood from squeezing the blade when it closes in on itself due to internal stresses?

If the wood is closing inward and pinching the blade it has nothing to do with the fence. If the cut piece is curving toward the fence a shorter fence can be of some benefit.

What gauge is your short extension cord?

[Alfred Hess]

Yes the last time I blew a fuse it was an issue with the wood closing. I was having a bit of a hard time visualizing how the short fence was going to help with this. Sometimes when I have a wood closing issue I stop the saw and hammer little wedges into the kerf.

My extension cord is not heavy duty but it is only six feet.

However. I think people are focusing too much on the fuse blowing issue. Not that I don't appreciate all of the good tips for ripping thick wood.
I am going to implement much of it.

At this time my issue is the following:

I need more power in my garage. At this time I can't run dust extraction and the table saw with a heavy load at the same time.
My reason for switching the saw to 220v has as much to do with freeing up one 110 volt circuit as it has to do with getting more power.
The 220 volt line that I have available to me has a 30 amp fuse because it also goes to the kitchen stove.
Since I don't plan to cook while I am in the shop I think it is a good temporary solution.

I am just worried that if something goes wrong during a cut that the 30 amp fuse won't blow and my saw motor will be cooked.

I am currently looking for a combination magnetic starter overload protector for the saw. Since the consensus seems to be that this saw doesn't have a built in breaker.




My main issue is this

[Doug Garson]

While you may not cook and work in your shop at the same time I believe the circuit feeding your stove by code must be a dedicated circuit for just the stove. You mentioned your extension cord is not heavy but only 6 feet, does it get hot when in use?

[David L Morse]

I am currently looking for a combination magnetic starter overload protector for the saw. Since the consensus seems to be that this saw doesn't have a built in breaker.




I think that's a good solution. Try this (https://www.amazon.com/Baomain-Magnetic-Starter-HUEB-16K-5-5-8-5A/dp/B01KDKPDKS/ref=sr_1_16?dchild=1&keywords=1.5hp+motor+starter+bighorn&qid=1587811308&sr=8-16).

Of course, if the trip point is properly set for your motor, it's going to trip a lot more often than the breaker does now.