SawStop Pro Electrical Issues - Tripping

[Dustin DuPrat]

I've had a SawStop Pro 1.75hp 220v saw for approx. 5 years now. From day one it tripped frequently - both the breaker as well as the thermal in the saw, especially when cutting hardwood. Even with a fresh Freud Glue-Line blade it has a super-tough time cutting 4/4 kiln-dried maple/birch, even walnut and poplar seem to be a chore with it tripping frequently. 8/4 anything...forget about it. We regularly have our blades sharpened, we use the appropriate blade for the corresponding materials/applications and don't cross blades from materials like MDF and melamine to plywood and solid wood. If blades appear contaminated we give them a quick wipe down to lower friction and buildup. We're pretty fastidious with our methodology and tools.

With that said, I've spoken with SawStop reps and they insist that it's either operator error (wrong blades with the wrong materials) the speed at which we're feeding the material (I've been doing this for 20+ years) or most likely, the way it's wired in our shop. They've indicated that they personally have these saws in their home shops and that they experience little trouble if any in the circumstances suggested. I've had multiple electricians look at our setup, read the literature, specifications etc and all insist that the way it's wired is above and beyond adequate. I've gone through more blades at $100+ each thinking maybe the sharpeners missed the boat and did a shoddy job, though they've worked perfectly on our other saw(s).

The saw and it's behaviour seems to cycle: some days if we're ripping hardwood it'll trip the breaker upwards of 20 times (yes, the breakers been replaced 4 times now to ensure that it isn't faulty) other times it'll kick the thermal as many times...and when I say 20 times I'm not talking during the duration of an 8 hour work day, I'm talking over the length of one 8-10' board that's already been trued on the jointer and planed. The saw doesn't have any reason to labour to the point where it's kicking - and with that said I had a 40+ year old Delta with a belt-driven 1.5hp motor that operates more reliably, as will my DeWalt job-site saw.

Both shops I had/have the saw in are climate controlled and dry. Dry material is only ever cut. The saw is cleaned frequently with compressed air and brushes. It's also hooked up to full dust collection from the cabinet base as well as the large SawStop over-arm collection system. I can't see anything situational based on settings that could be contributing to this issue.

Am I missing something here that SawStop isn't telling me, or even an electrician? SawStop had us replace the contractor box...didn't help a bit. Now they're MIA and likely sick of hearing from me as this has been an issue we've struggled against pretty much from day one. Any feedback from individuals with this saw - similar or contrary would be great peace of mind. I'd love to know - even if it's just me having this issue!

Any advice would be greatly appreciated, especially before I face what seems to be the inevitable and go down the route of investing in another costly saw.

Thanks in advance!

[Andrew Seemann]

Have you ever had an electrician there when it was tripping? It possibly could be that you are getting low voltage periodically in your shop. It is unlikely but possible. That would have the effect of increasing the amp draw and could make the motor run hotter as well. Ideally you would check the voltage to the machine when it is running right before it trips to see if you are getting at least 220 or so volts.

[glenn bradley]

with that said I had a 40+ year old Delta with a belt-driven 1.5hp motor that operates more reliably, as will my DeWalt job-site saw

I don't know about the Delta but the DeWalt is certainly running on a different circuit. The draw may not be all that different due to the higher voltage on the Saw Stop. With the breaker replaced that would lead me to the wire and the connections. I forget how often one should torque breaker connections and I have to admit I have only done it when moving into a new space or when a problem presents itself. I certainly have found loose connection points during those efforts.

I would like to hear from someone who has many years in the electrical motor field since by comparison, my experience would be minor. I have not had an induction motor, that I know of, present wide swings in amperage draw. Unfortunately using the "which one tripped first" method of troubleshooting isn't super helpful. Is it possible to run the saw on a different circuit when it is doing its trick? Maybe just pulling the 220 kit and going back to 110v could be your fix.

[Andrew Hughes]

I was thinking the same thing as Andrew S. If it were my saw I’d be looking at how many Amps the saw was pulling before it tripped. It must be going over it’s Fla. Voltage sagging is very common for me here in So Cal. I think we have the dirtiest power and politicians.
During the summer when I start my big bandsaw the voltage drops from 235v to 112 and the lights dim. Thankfully it’s not very long.

[Paul F Franklin]

As I'm sure you know, that saw should have no problem ripping 4/4 hardwood.

I would verify that the motor is getting 240 volts--at the motor terminals--when it is operating under load. If it is, you have a motor problem, either an incorrect value run capacitor, a bad run capacitor, or a bad motor.

Another thought....if that model can be wired for 240 or 120, make sure it's wired for 240.

[Bruce King]

Describe the wiring path and sizes from the receptacle all the way to the outside meter.
Pictures of each panel and the meter too.

[Dave Mills]

I've had a SawStop Pro 1.75hp 220v saw for approx. 5 years now.

To my knowledge the 1.75hp PCS is a 110V machine. Or did they make a 220V version 5 years ago?

[Richard Baxter]

Get an amp probe and check amperage as you are running the saw. 1.75HP to me is too small especially cutting 4/4 hardwood. Minimum should be 3HP

[David L Morse]

Your troubleshooting to date strongly points to the motor, not the breakers, nor the saw's overload protection. (The multiple tripping is caused by the long time constants of the protection devices. That's by design, it's not an issue.)

Some questions:

Who did the 240V conversion? (According to the SS website 120V is standard and a conversion kit is available)

Did your multiple electricians check the wiring at the motor, not just the switch box?

Does the saw slow down when cutting the 4/4 material? (in case you're a musician, the change in pitch from no load to full load should be less than a semitone)

A request:

Get an ammeter and check the idle (no load) current. If the saw will allow it, take the blade off for that test. No real need to check loaded current, we already know that's too high.

A comment:

If you've been operating the saw this way for five years the motor likely does not have much life left. That's a lot of time spent at an excessive temperature rise. Aging rate approximately doubles with every 10°C increase in temperature.

[Brian Tymchak]

Any chance you have an undersized extension cord run to that saw?

Edit: I guess in retrospect that wouldn't explain the breaker tripping.

[Brian Tymchak]

Get an amp probe and check amperage as you are running the saw. 1.75HP to me is too small especially cutting 4/4 hardwood. Minimum should be 3HP

Not sure if you are saying that generally you need a 3 hp saw to cut 4/4. If so, I disagree. I've been cutting 8/4 hardwoods on my 1.5hp Ridgid TS3650 for 10+ years.

[Bill George]

Having been in the electrical trade since 1962 and retired as a master in 2007 I can safely say I have been around a while. There are electricians who wire houses and I was not one of those. I did commercial and industrial.

What size wire and what size breaker feeding the motor?

Is it on an extension cord? If so what size wire and how long a run?

[Bill George]

Any chance you have an undersized extension cord run to that saw?

Edit: I guess in retrospect that wouldn't explain the breaker tripping.

Yes it will. Undersized or long cord would cause excessive volt drop on start up. Motors draw 3 - 4 times FL rated current on start up. The breaker or TD fuse Usually has enough time delay built in to allow the motor to start, IF the voltage says constant, or nearly so.

[Tim Nguyen]

I have the PCS 1.75 and have no problem once I moved my plug to a dedicated 110 volts 15 amp service. I suspect you are not using a 220 volt circuit. Does anyone know what style SawStop 220 volts plug looks like? I suspect the plug to have a different configuration from a standard 110 volts and can not plug into a 110 volt outlet. If you have a 220 volt service, than I would suspect the saw first.

[Thomas McCurnin]

If the saw was operating perfectly for five years and nothing has changed, it can’t be the wiring and must be the saw motor.

[Ron Selzer]

voltage and amp readings UNDER LOAD would definitely point to where the problem is
Ron

[Bill George]

If the saw was operating perfectly for five years and nothing has changed, it can’t be the wiring and must be the saw motor.

This is what he posted above "'I've had a SawStop Pro 1.75hp 220v saw for approx. 5 years now. From day one it tripped frequently "

Yes dedicated 120 volt 20 amp plugs are different than standard.

[Paul F Franklin]

If the saw was operating perfectly for five years and nothing has changed, it can’t be the wiring and must be the saw motor.

Tom, the way I read the op, the saw has not operated correctly since first purchase....

[Frank Pratt]

There's been lots of good suggestions & questions raised. We need more feedback from the OP to be of further help. If not done already, voltage & current readings need to be done at the saw while under load.

[Malcolm McLeod]

I've had a SawStop Pro 1.75hp 220v saw for approx. 5 years now. From day one it tripped frequently ...

Has the saw ever operated 'normally' in your view? (...no trips for an hour, a day, a week?)

If as suggested, you can't get an ammeter on it, will it run for 10-15 minutes unloaded?

In addition to who performed the 120>>240V conversion, when was the conversion done? ...Day 1? (Looking for info about 'normal' operation before the conversion.)

Mr. Morse may be onto something wrong in the motor wiring. ...IMHO.

[Scott Bernstein]

I have a SawStop "1.75" PCS which I've used for about 5 years. When I purchased it, it came wired for 110V and used it that way for three years. It was on a dedicated 20Amp circuit and even then it did have trouble with really, really hard and thick wood (like 12/4 Hickory). Even with very slow feeding and a ripping blade it would trip the internal overload protection or the breaker. The motor would bog down sometimes on hard 6/4 or 8/4 material but usually with 4/4 material it was always OK. Eventually I did the upgrade to the bigger 3HP motor and 220V conversion myself and now it never bogs down on anything, no does it trip the breaker.

I agree with the questions here - is the OPs saw really wired for 220?

[Frank Pratt]

As long as everything is wired correctly to code, there is no advantage to running a saw on 120V or 240V. The question is whether the saw was correctly converted to 240V. The 120V electronics would likely evaporate in short order if connected to 240V, so that isn't the issue. If they were changed out for the 240V items, but the motor connection were not properly converted, then that could be the cause of all the tripping & lack of power.

My FIL gave me has Rockwell/Beaver table saw because it was so underpowered. It turned out to be wired for 240V, but had a 120V plug on the cord. The symptoms the OP relates are exactly what that saw of mine acted like. Once I rewired the motor, it ran like it should. Otherwise, the saw was a real POS & I eventually unloaded it for $50.

[Bert McMahan]

As long as everything is wired correctly to code, there is no advantage to running a saw on 120V or 240V. The question is whether the saw was correctly converted to 240V. The 120V electronics would likely evaporate in short order if connected to 240V, so that isn't the issue.

I've never looked inside a Sawstop but the control electronics might have a universal power supply that can handle 120 or 240. The fact that they didn't blow *may* not mean he's in the clear. Then again, it might be, I just don't know. I DO know that there are many power supplies out there that can auto-adjust to either.

I do agree that it sounds like the motor isn't wired right. Check inside the box for the connections to be nice and secure.

Also... any change you have some really terrible blade alignment to your fence? Could it just be binding a lot? I can't imagine how much you'd need for this much effort but I think the other posters have the electrical troubleshooting pretty well in hand.

[Frank Pratt]

I've never looked inside a Sawstop but the control electronics might have a universal power supply that can handle 120 or 240. The fact that they didn't blow *may* not mean he's in the clear. Then again, it might be, I just don't know. I DO know that there are many power supplies out there that can auto-adjust to either.


Multi-voltage electronics are increasingly common, but the SawStop uses different control parts for 120V & 240V.

WRT power, my aforementioned piece of crap saw, it had a 3/4 HP motor & didn't have a problem cutting 4/4 hardwood with a thin kerf blade. Slow, yes, but doable.

[Mike Henderson]

I had an old Craftsman contractor saw with a small HP motor at one time. I had to be careful cutting anything thick - very slow feeding. When overloaded, the saw would stall but the breaker would not trip as long as I pulled the work back and let it spin back up again.

But maybe that was because the motor was so small - maybe it didn't draw a lot of excess current even when stalled. The motor in the OP's SawStop is 1.75HP which is about the biggest you can run on a 120V 15 amp circuit so when it stalls it may draw enough to trip the breaker.

With a thin kerf blade, that saw should cut 4/4 just fine. Even with a full kerf blade it should cut 4/4 fine. To diagnose it, I'd want to know the voltage at the motor and the amperage when it trips the breaker. I'd suspect a problem with the motor if the voltage is correct.

Mike

[Bert McMahan]

Ah good to know, thanks Frank.

[Melvin Feng]

all this talk about wiring makes me wondering if the plug is a 4 prong plug, and rather than use the two hots, it is using the neutral, but the motor is wired for 220v. I don't know if this scenario would cause the tripped breakers, but it would definitely cause the lower power. I don't know how inductive motors react to half of the expected voltage, but getting out a good multimeter would be an easy way to diagnose all of this.

I don't know if there is a way to measure the resistance of the coil windings, but another thought is that there could be a pinch or corrosion or something causing the resistance to be different than expected, causing problems with the motor.

[Bill George]

I downloaded the Owners Manual and it comes pre-wired for 120 vac with a standard plug to rewire to 230 vac is involved and hoping I can paste here. Motors do not need a neutral just two hot wires L1 & L2 and a equipment grounding wire. Once again the questions what size wire and what size circuit breaker?
BTW motors do run better on 240 than 120 volts. The saw Must be on a #12 wire or larger and 20 amp breaker dedicated circuit.

445702

[Frank Pratt]

[QUOTE=Bill George;3073437]BTW motors do run better on 240 than 120 volts.QUOTE]

As long as the circuit is wired to code, that statement is completely false & a common misconception. A dual voltage motor has windings that are connected in series for the higher voltage or parallel for the lower voltage. Each winding sees the same voltage whichever way the motor is connected.

[Frank Pratt]

all this talk about wiring makes me wondering if the plug is a 4 prong plug, and rather than use the two hots, it is using the neutral, but the motor is wired for 220v. I don't know if this scenario would cause the tripped breakers, but it would definitely cause the lower power. I don't know how inductive motors react to half of the expected voltage, but getting out a good multimeter would be an easy way to diagnose all of this.

I don't know if there is a way to measure the resistance of the coil windings, but another thought is that there could be a pinch or corrosion or something causing the resistance to be different than expected, causing problems with the motor.

That's a good thought, but I doubt the 240V contactor would pull in on 120V. The motor will run, but will take a long time to come up to speed & be very lacking in power.

[Bill George]

[QUOTE=Bill George;3073437]BTW motors do run better on 240 than 120 volts.QUOTE]

As long as the circuit is wired to code, that statement is completely false & a common misconception. A dual voltage motor has windings that are connected in series for the higher voltage or parallel for the lower voltage. Each winding sees the same voltage whichever way the motor is connected.

Well larger motors that have a choice of either supply voltage start and run better on 230 volts. I am (was now retired) a licensed master electrician and been so since 1964. I am well aware of how to wire motors and controls, that what I did. If it was a misconception I was fooled for over many years..... :). Worked with 3 and single phase motors, VFD's and controls. Ask me about Code passed tests in Minn and Iowa.

[David L Morse]

[QUOTE=Frank Pratt;3073565]

Well larger motors that have a choice of either supply voltage start and run better on 230 volts.

Can you provide actual measurements of the performance parameters that are improved and by how much?

[Frank Pratt]

[QUOTE=Frank Pratt;3073565]

Well larger motors that have a choice of either supply voltage start and run better on 230 volts. I am (was now retired) a licensed master electrician and been so since 1964. I am well aware of how to wire motors and controls, that what I did. If it was a misconception I was fooled for over many years..... :). Worked with 3 and single phase motors, VFD's and controls. Ask me about Code passed tests in Minn and Iowa.

Nope, that just isn't so. The only time a motor will run better on the higher voltage is if there is excess voltage drop because of inadequate wire size. I've done a bit of study on motors & have not seen anything that would support your statement. Can you share your source?

If you're looking at the whole installation picture, then it is better to wire a motor for the higher voltage because of reduces wiring costs associated with it. But the motor will run no better on one voltage or the other.

I'm also a master electrician, but only since around 1982, so you've got me beat there :)

[Bill George]

Over 50 years in the trade, most of which was commercial and industrial side, and design installation of controls. Last 12 years I taught the subject. Do a Google search and educate yourself. Large dual voltage single phase motors start and run better on 230 vs 115 volts.

Any real world electrician will know that, one that has worked in the trade, that is.... ;) look it up and prove me wrong.

Here is one after a 10 sec search https://www.hobby-machinist.com/threads/advantage-to-230v-single-phase-vs-115v.77415/

Yet another..... https://www.practicalmachinist.com/vb/general-archive/1-hp-motor-should-i-wire-220-110-a-83411/

Another,,,,......>> http://jpandersonwell.com/what-electrical-voltage-works-best-for-most-pumps.php

This is almost to easy..... https://www.powertransmission.com/issues/0917/baldor-basics.pdf

Or join this forum and ask the question ??? https://www.mikeholt.com/

[Mike Henderson]

. Large dual voltage single phase motors start and run better on 230 vs 115 volts.



Nope, assuming that the circuit supplying the motor is adequate, the motor will perform exactly the same on 120 volts as on 240 volts. What happens in many situations is that the 120 volt circuit cannot provide the amperage needed without a significant voltage drop and that causes the motor to perform poorly compared to operation at 240 volts. But if the circuit is adequate, performance is the same on either voltage.

Mike

[Regarding your 50 years of experience: That would be of value if you were discussing things you found in the real world. For example, if you said that most motors that were wired for 120 volts were on circuits that were not adequate for the amperage demand you would be believed. But when you try to dismiss well proven electrical theory with a claim of 50 years experience you're not going to be believed. If you want to argue that a motor operating a 240 volts performs better than if that same motor is operated at 120 volts you're going to have to provide reasons based on electrical theory and the mathematics to back it up. I don't think you're going to be able to do that.]

[Bill George]

I am going to un follow this Thread and let you Experts keep on, I suggest you read and learn from the Links I have posted.

[David L Morse]

I am going to un follow this Thread and let you Experts keep on, I suggest you read and learn from the Links I have posted.

I looked at those links. None of them really support your claims.

As has been stated, any perceived differences in performance are due to the infrastructure, not the motor.

[Frank Pratt]

Hmm, I thought I was a real world electrician :(
Anyway, Bill has bailed on the thread, but I thought I'd comment on his links. There are a bunch of forum posts that talk of higher voltage installations being better for cost reasons and also "220V rules" posts from 'experts' who don't even know that there is no 220V here. The other articles talk of the benefits of higher voltage with regards to voltage drop, particularly in long circuit runs. I could find no factual information saying the the motor performs better on the higher voltage.


Over 50 years in the trade, most of which was commercial and industrial side, and design installation of controls. Last 12 years I taught the subject. Do a Google search and educate yourself. Large dual voltage single phase motors start and run better on 230 vs 115 volts.

Any real world electrician will know that, one that has worked in the trade, that is.... ;) look it up and prove me wrong.

[Mike Henderson]

I think many people believe that a motor run at 240 volts performs differently than when run at 120 volts because they've had situations where the supply circuit is not adequate at 120 volts. And sure enough - in that situation - the motor does perform better when operated at 240 volts. The mistake they make is to believe the difference in performance is due to the motor, rather than the supply circuit.

Mike

[Frank Pratt]

I think many people believe that a motor run at 240 volts performs differently than when run at 120 volts because they've had situations where the supply circuit is not adequate at 120 volts. And sure enough - in that situation - the motor does perform better when operated at 240 volts. The mistake they make is to believe the difference in performance is due to the motor, rather than the supply circuit.

Mike

That's exactly it Mike. There are even electricians that think that :)

[Jim Dwight]

I've had a PCS with 1.75hp motor for several years but I don't think it's five yet. I run it on a 120V 20A circuit. I initially did not have any issues with it and power but when I was making a bunk bed with legs close to 3 inch square out of softwood, I had trouble with the rips. I used it to make a queen sized bed with similar sized, but shorter, softwood legs and a queen sized bed with cherry legs about 3 inches square. Until the bunk bed legs, no issues. I mainly used full kerf blades. When I started having issues with the bunk bed legs I started trying different blades. I think I had on a nearly new Infinity 50 tooth all around blade and switched to an Infinity 24 tooth rip blade, both full kerf. It didn't seem to help much. So I went to a not close to new but still serviceable Freud 24 tooth ripping blade and it cut much better. Next I tried a thin kerf Freud 24 tooth ripping blade and it cut at my normal feed rate, no issues. I think the wood was closing up on the blade a little and that was part of the issue.

I had lesser issues cutting a 1 inch thick oak tread I was recycling. The thermal overload tripped on a short and not that deep rip. But I noticed the wood was pinching the blade and put a wedge in the kerf and the issue disappeared.

I now use only thin kerf blades on my PCS. I have done some near 3 inch rips with the Freud Fusion all around blade that is on it at the moment. But I am pretty sure if I get into wood that wants to close up right after the riving knife again I will need to switch to a ripping blade. But that pinching is less likely, I believe, with the thin kerf because the thickness of the riving knife is very close to the thickness of the steel plate of the blade - closer to the kerf size. With a 1/8 kerf blade, it is easier to adjust the riving knife position but it is easier for the wood to close up despite the riving knife and pinch the blade.

I've used 110V table saws for around 50 years and I do not remember one that wanted thin kerf blades as badly as my PCS. Wiring may well be the issue but if you haven't tried a thin kerf blade I would.