Unisaw disconnect

[acer66]

Hello,

I have a new to me old Unisaw with a 1&1/2HP wired for 240V with a GE CR1062R6A disconnect/switch and after around 10 min of very light cutting the switch cuts out and I can not reset it.

After it cools down, I guess, I hear a click and off I go.

Temperatures are low and the motor and switch are cold when I touch them.


Any thoughts?

Thank you.

 

[nh_yota]

Might need to upsize the overload strips.

 

[nadogail]

Might need to upsize the overload strips.

Agreed with the previous poster, you may need to change to a higher value “heater”.

 

[Bert_]

Look for numbers stamped on the heater. Should also be a chart on the cover that tells you what fla it's rated for. Needs to match the motor

 

[pattenp]

Why does 1-1/2 HP saw even need that style switch?

 

[wyliesdiesels]

can you tell us what size the current overloads are? they should have a number stamped on them

also, post a picture of the motor nameplate.

Does the saw have built-in overload protection ie. red button on end? if so you can ditch this starter and get a start/stop contactor without an overload relay.

 

[walta]

Why does 1-1/2 HP saw even need that style switch?

Many older motors made before 1970 or so were not built with internal overload protection and require this type of “switch” called a motor starter. If a switch were to be substate for a motor starter and someone were to feed the wood too fast into a dull blade the motors windings will go up in a cloud of smoke long before the breaker in the panel trips.

Walta

 

[wyliesdiesels]

if your motor has built-in overload protection, then just swap your current starter with one of these-

Leviton MS-602 60a motor starter

Amazon.com

 

[Bert_]

if your motor has built-in overload protection, then just swap your current starter with one of these-

Amazon.com

I mean that would definitely work. To me it makes more sense just to buy the correct heater for $15 or so.

 

[wyliesdiesels]

I mean that would definitely work. To me it makes more sense just to buy the correct heater for $15 or so.

if the motor has built-in OL protection why bother with that?

 

[Bert_]

if the motor has built-in OL protection why bother with that?

Because the motor rated switch you linked is $75 and then you have to unwire and remove the existing manual starter, mount the new one and wire it back up. To replace the heater only takes two screws.

It's not a huge deal but what do you gain for all the extra work and expense?

 

[Raisedonadeere]

Because the motor rated switch you linked is $75 and then you have to unwire and remove the existing manual starter, mount the new one and wire it back up. To replace the heater only takes two screws.

It's not a huge deal but what do you gain for all the extra work and expense?

 

[mike93lx]

Because the motor rated switch you linked is $75 and then you have to unwire and remove the existing manual starter, mount the new one and wire it back up. To replace the heater only takes two screws.

It's not a huge deal but what do you gain for all the extra work and expense?

There is an open box one in Amazon warehouse for just $26, if someone did want to go that way

 

[acer66]

There is an open box one in Amazon warehouse for just $26, if someone did want to go that way

Link?

 

[mike93lx]

Link?

If you look on the Amazon page, it will either be right below the button to buy or in a area labeled something like "new&used from..."

 

[acer66]

Thank you for all the responses.
I should clarify that the saw is newish to me and I have cut more with not problem.
Here some pics.



I read 81D and 548

 

[acer66]

If you look on the Amazon page, it will either be right below the button to buy or in a area labeled something like "new&used from..."

Thank you

if your motor has built-in overload protection, then just swap your current starter with one of these-

Leviton MS-602 60a motor starter

Amazon.com

I double checked and I did not find any reset button on the motor.

 

[Norcal]

Looks like a C995A heater is required, there are used equipment dealers that sell heaters/ thermal elements, I bought a Rockwell 6" jointer with a 3 phase motor, swapped it for a single phase motor but the Rockwell LVC (Low Voltage Control) starter used a GE overload relay, I still have not bothered to source a new one as when GE was carried at a local supply house they did not handle GE's industrial controls now nobody has any GE locally.

 

[rlitman]

...I double checked and I did not find any reset button on the motor.

Your nameplate clearly states "MOTOR NOT THERMALLY PROTECTED", so no, you will not find a reset button.

Looks like a C995A heater is required, there are used equipment dealers that sell heaters/ thermal elements, I bought a Rockwell 6" jointer with a 3 phase motor, swapped it for a single phase motor but the Rockwell LVC (Low Voltage Control) starter used a GE overload relay, I still have not bothered to source a new one as when GE was carried at a local supply house they did not handle GE's industrial controls now nobody has any GE locally.

Close, but you made the same typo as the ebay listing I found.
The heater is CR123C955A

This guy's selling a 3 pack:

General Electric CR123C955A Heater for Overload Relay C995A Set Of 3 With Screws | eBay

Find many great new & used options and get the best deals for General Electric CR123C955A Heater for Overload Relay C995A Set Of 3 With Screws at the best online prices at eBay! Free shipping for many products!

www.ebay.com

They can be found on Amazon too:

GENERAL ELECTRIC CR123C955A 480V 9.19A New: Amazon.com: Industrial & Scientific

GENERAL ELECTRIC CR123C955A 480V 9.19A New: Amazon.com: Industrial & Scientific

www.amazon.com

 

[acer66]

Your nameplate clearly states "MOTOR NOT THERMALLY PROTECTED", so no, you will not find a reset button.


Close, but you made the same typo as the ebay listing I found.
The heater is CR123C955A

This guy's selling a 3 pack:

General Electric CR123C955A Heater for Overload Relay C995A Set Of 3 With Screws | eBay

Find many great new & used options and get the best deals for General Electric CR123C955A Heater for Overload Relay C995A Set Of 3 With Screws at the best online prices at eBay! Free shipping for many products!

www.ebay.com

They can be found on Amazon too:

GENERAL ELECTRIC CR123C955A 480V 9.19A New: Amazon.com: Industrial & Scientific

GENERAL ELECTRIC CR123C955A 480V 9.19A New: Amazon.com: Industrial & Scientific

www.amazon.com

Thank you and paying attention to details is not one my strongest qualities.

 

[walta]

Is it me or what but I can’t find a number on the heater in the chart?

Was the motor stater and heater all installed on the saw when it came to you?

If they came together there is some possibility, they are a matched set but I would not put the saw to work until, I was sure. You are betting $400 worth of new motor on getting this right.

Walta

 

[rlitman]

Is it me or what but I can’t find a number on the heater in the chart?...

The heater pictured? I doubt the number on it is the model number, but you're right in as much as any numbers on the heater pictured are not on the chart.

Thank you and paying attention to details is not one my strongest qualities.

Mine either apparently. Your motor plate shows 9.6A @ 230V. However, it does not mention service factor.
I picked the heater off the chart for 9.6A, but overlooked the text that says that for a 1.0SF motor, you should multiply the current by 0.9, so you really want the heater for 8.64A, which would be a CR123C867A. The difference is quite small, and the other heater may be fine, but if you haven't ordered a heater yet, this one is cheaper too.

 

[mike93lx]

Curious, what is the purpose of these heaters?

 

[rlitman]

Curious, what is the purpose of these heaters?

They heat up a bimetallic element (basically a thermostat) that cuts off the power when it gets hot. The heating element is wired in series with the motor, so any current that goes through the motor goes through the heater too. If too much current runs through the motor, the heater gets too hot, and the switch shuts down, protecting the motor from being overheated.

As you go up in motor size, you pick a heater that has less and less heat output.

 

[Bert_]

Curious, what is the purpose of these heaters?

Detects current and protects the motor from overload.

They are old technology, but work very well. Been around as long as there have been motors.

 

[mike93lx]

Detects current and protects the motor from overload.

They are old technology, but work very well. Been around as long as there have been motors.

Thanks. So essentially a reusable fuse?

 

[rlitman]

Thanks. So essentially a reusable fuse?

A thermal circuit breaker, without the magnetic half. Not self-resetting though, so not exactly like the automotive type, though otherwise similar

Ordinarily, we think of a fuse as blowing rather quickly. Being a thermal device, this is designed to trip slowly, and match the thermal characteristics of the motor windings.

 

[Bert_]

Thanks. So essentially a reusable fuse?

The trip curve is much slower than even a time delay fuse. The heater is also chosen to match the motor current, there are hundreds of sizes available.

 

[acer66]

Is it me or what but I can’t find a number on the heater in the chart?

Was the motor stater and heater all installed on the saw when it came to you?

If they came together there is some possibility, they are a matched set but I would not put the saw to work until, I was sure. You are betting $400 worth of new motor on getting this right.

Walta

It came with the saw but there was also another disconnect daisy chained also which I discovered was mechanical broken so I removed that and run the saw off this one.
As I said it sometimes works for longer and while I say it is not hot I got this saw at the beginning of the winter so maybe the lower temperatures might have made it work longer.

I hope not on a new motor, new ones got so pricy.

 

[acer66]

The heater pictured? I doubt the number on it is the model number, but you're right in as much as any numbers on the heater pictured are not on the chart.


Mine either apparently. Your motor plate shows 9.6A @ 230V. However, it does not mention service factor.
I picked the heater off the chart for 9.6A, but overlooked the text that says that for a 1.0SF motor, you should multiply the current by 0.9, so you really want the heater for 8.64A, which would be a CR123C867A. The difference is quite small, and the other heater may be fine, but if you haven't ordered a heater yet, this one is cheaper too.

Good that I am not the only one but extra thanks to you for checking again and I have not bought them yet so that is good news.

 

[walta]

Let me try again but with photos.

Is anybody able to find a number on this heater that corresponds with a number on the chart for this starter?

I for one can’t

If you are going it run the motor on 120 volts the motor will draw up to 19.2 amps the heater needs to 5-10% over sized so I think you want a heater 20.16 – 21.12 and I find C214B on the chart.

General Electric C214B Overload Thermal Heater Element for sale online | eBay

Find many great new & used options and get the best deals for General Electric C214B Overload Thermal Heater Element at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Walta

 

[rlitman]

...If you are going it run the motor on 120 volts the motor will draw up to 19.2 amps the heater needs to 5-10% over sized so I think you want a heater 20.16 – 21.12 and I find C214B on the chart...

Nope. Read the instructions next to the chart. The chart is already over-sized by assuming a 1.25 SF, and this motor has no SF stated, so it is 1.0.

At 120V, 19.2A x 0.9=17.28A, which calls for CR123C180B. But the OP is using 240V, so this is a pointless exercise. Also, remember that motor current is a function of power output. Spinning at idle, the motor current will be much lower than the FLA. FLA is reached when the motor is operating at rated HP (not taking SF into account). No matter how busy a shop (even in a factory production line), a tablesaw will be at idle for more time than it spends cutting, so you don't need to oversize the heater.

As for the OP's wrong heater, it's an 81D548, which not only doesn't belong in this starter, but is rated 6.35-6.87 amps. That would explain why it is cutting off.

 

[acer66]

For the first time I used the saw now extensively ripping a bunch of 2x’s in warmer weather and it powered right through everything without problems.

Thank you all for the help provided.

 

[Zeke]

This thread came up at the bottom of another thread page as recommended 'similar' reading. I was just going to note that the $75 switch Wylie linked in post #8 and looked up by Bert in post #11 is now $107.

Ouch.

 

[wyliesdiesels]

This thread came up at the bottom of another thread page as recommended 'similar' reading. I was just going to note that the $75 switch Wylie linked in post #8 and looked up by Bert in post #11 is now $107.

Ouch.

and they were about $30 when i bought one in 2014

 

[acer66]

Perfect timing since the saw acted up again after ribbing a bunch of 2x’s.

Stopped working, could not press the off button in and after a few minutes it worked again but cut out after a few minutes again.

Thinking about replacing the whole switch box with a magnetic one because the way I understand it it can not be the motor since it has no overheat protection.

Right or could the motor still be the issue?

Which to me would be weird because I would not think it would cool down that fast.

Thank you.

 

[Zeke]

Have you checked all the wiring? Maybe Ohm it out.

 

[Bert_]

Perfect timing since the saw acted up again after ribbing a bunch of 2x’s.

Stopped working, could not press the off button in and after a few minutes it worked again but cut out after a few minutes again.

Thinking about replacing the whole switch box with a magnetic one because the way I understand it it can not be the motor since it has no overheat protection.

Right or could the motor still be the issue?

Which to me would be weird because I would not think it would cool down that fast.

Thank you.

PUT THE CORRECT HEATER IN!

Looks like post #22 lists a CR123C867A heater. A quick Google shows the right thing, $10-20 part

 

[rlitman]

PUT THE CORRECT HEATER IN!

Looks like post #22 lists a CR123C867A heater. A quick Google shows the right thing, $10-20 part

Well, unless he went off-thread, either he got the CR123C867A (correct answer from post 22), or the CR123C955A I discussed in post 19. If he got the 955A, it should run the motor even hotter before cutting out, so at this point, maybe the heater choice isn't the issue.

Something to consider is that while motor current should be the only source of heat for the heater, if it has a loose connection, that could make the heater get hotter. Also, dust in the switch body can retain heat, and dust in the motor windings can also hold heat, and a hot motor has more resistance, so it draws more current.

Do you have a compressor? Can you blow out the switch box? Maybe make sure the motor fan cover isn't caked with dust and is getting good flow (I'd say to blow out the windings, but this looks like it is TEFC).

 

[Bert_]

Just from the posts I got the feeling never got around to replacing the heaters. I could be wrong