# Delta dust collector motor Question



## ryan50hrl (Jun 30, 2012)

Ok, so I have a delta 1.5 Hp dust collector, motor plate says it draws 12 amps on 110, 6 on 220, So I ran a 110 circuit, 14-2 wire on 15 amp breaker. you flip the switch, it started ramping up and then blows the breaker. It took maybe a second to blow the breaker. So, I plug it into a 20 amp circuit.....it runs fine (although dimming my lights in the shop which were on a different circuit, but same 60 amp panel). So I swap it over to 220, put in a double pole breaker, and it runs now.....however it still dims the lights......and i pulled out my amp clamp meter, and on 110, it momentarily draws 85 amps when starting..... 

Anyone have any ideas....i'm thinking bad capacitor??? Many motors i'm finding online say they won't start at all and just hum with a bad capacitor....so is it possible to have a capacitor going bad?? Or is it since theres no real load on the motor on start up it can power through??


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## Shop Dad (May 3, 2011)

New? Used? Picture?


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## troyd1976 (Jul 26, 2011)

wow was that 85 amps?

id check that capacitor with a meter..incause ya dont know how (i had to look it up) heres a link that seems to give a good run down on the settings, etc. on your meter 

http://www.squidoo.com/how-to-check-capacitor


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## ryan50hrl (Jun 30, 2012)

Yep...its the capacitor.....and yep...max draw of 85 amps at motor start up


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## J.C. (Jan 20, 2012)

Have you used the dust collector before and not have any problems? I can't say I've checked start up current draw on tons of motors but 85 amp draw doesn't sound crazy. Are you using a new breaker or an old one?


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## ryan50hrl (Jun 30, 2012)

Brand new breaker.....brand new wiring.....brand new outlet......the dust collector is 1.5 hp. 

My table saw is 1.75 hp.....max draw at start up is 18 amps......

Both induction motors...


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## TimPa (Jan 27, 2010)

upon start-up a motor draws huge amounts of current, 10 to 100 times the rated running amps. A "time-delay" fuse will overlook this in-rush current for a specified time and amount. circuit breakers have the same time delay built into them, so a special breaker is not required for motor circuits. 

there are other factors that can affect your issue, wire length, cb age (and how many times it's been tripped), motor load during start, etc.. start cap integrity can be one of them


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## rrich (Jun 24, 2009)

Your meter is probably correct in its reading. But you're likely seeing the peak reading. The peak is probably over a single AC cycle and the norm. The last time that I measured something like that with an oscilloscope and a .01 ohm resistor, the second cycle was substantially less current.

I suspect that the wiring that feeds the 60 Amp panel in the shop is inadequate. That would be the first thing that I would look at, it's only 4 screws to check.


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## TomC (Oct 27, 2008)

troyd1976 said:


> wow was that 85 amps?
> 
> id check that capacitor with a meter..incause ya dont know how (i had to look it up) heres a link that seems to give a good run down on the settings, etc. on your meter
> 
> http://www.squidoo.com/how-to-check-capacitor


It hard to test with a digital multi meter. Easy with an old analog meter.
Tom


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## ryan50hrl (Jun 30, 2012)

rrich said:


> I suspect that the wiring that feeds the 60 Amp panel in the shop is inadequate. That would be the first thing that I would look at, it's only 4 screws to check.



Nope. I put it in two weeks ago.....6 gauge copper


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## TimPa (Jan 27, 2010)

ryan50hrl said:


> Nope. I put it in two weeks ago.....6 gauge copper


6 ga neutral also?


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## ryan50hrl (Jun 30, 2012)

Yep. Sure did


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## TimPa (Jan 27, 2010)

ryan50hrl said:


> Ok, so I have a delta 1.5 Hp dust collector, motor plate says it draws 12 amps on 110, 6 on 220, So I ran a 110 circuit, 14-2 wire on 15 amp breaker. you flip the switch, it started ramping up and then blows the breaker. It took maybe a second to blow the breaker. So, I plug it into a 20 amp circuit.....it runs fine (although dimming my lights in the shop which were on a different circuit, but same 60 amp panel). So I swap it over to 220, put in a double pole breaker, and it runs now.....however it still dims the lights......and i pulled out my amp clamp meter, and on 110, it momentarily draws 85 amps when starting.....
> 
> Anyone have any ideas....i'm thinking bad capacitor??? Many motors i'm finding online say they won't start at all and just hum with a bad capacitor....so is it possible to have a capacitor going bad?? Or is it since theres no real load on the motor on start up it can power through??


what did it draw on 220v (you have to clamp both hots)?
what size breaker on the 220v ckt?


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## J.C. (Jan 20, 2012)

This thread peaked my curiosity so, I decided to check the start up current draw on a couple dust collectors and a table saw. Everything I tested runs on 220v. 

The first dust collector has a name plate rating of 13 amps. It drew 52 amps at start up and ran at 8.4 amps. I couldn't read the hp rating on the tag.

Second dust collector is a 5 hp with a name plate rating of 23 amps. It drew 100-105 amps at start up and ran at 17.8 amps.

Table saw is a 5 hp with a 20 amp name plate rating. Most times it drew 73 amps at start up but it wasn't uncommon to see it draw 93 amps at start up. Ran at 3.8 amps. 

Back when I first hooked the table saw up, I had to change the breaker because it kept tripping it at start up. It's been about a year now and haven't had any problems since then. 

Not that any of this really helps you out but I thought I'd share.


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## TomC (Oct 27, 2008)

TimPa said:


> what did it draw on 220v (you have to clamp both hots)?
> what size breaker on the 220v ckt?


If you are wired for 220v you only need to put the clamp on amp meter on one of the black wires. You should have the same amperage in both wires, one amps flowing in and one of them flowing out.
Tom


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## ryan50hrl (Jun 30, 2012)

Well I guess mines not too far off from your smaller collector, I'm torn between tearing the motor apart to look for a problem, or just letting it run


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## GROOVY (Apr 27, 2008)

I had a simular problem with an older stored for a long time motor, it had a centrifugal switch thing inside that was hung up..


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## TimPa (Jan 27, 2010)

TomC said:


> If you are wired for 220v you only need to put the clamp on amp meter on one of the black wires. You should have the same amperage in both wires, one amps flowing in and one of them flowing out.
> Tom


What was I thinking? - you are right. it would read zero my way.


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## bsandor (Feb 5, 2020)

I know this is an old thread, but I am having a similar problem with a Delta 50-850 1-1/2HP dust collector. I've owned it since new, for probably close to 15 years. Within the last few months, it has more and more frequently been tripping it's built-in breaker on startup. Now it will not start at all - it always trips after a second or two. I've replaced both starter capacitors (I didn't realize at first there were two - 25uF and 200uF). I've replaced the built-in breaker. I've cleaned and reset and tested the centrifugal startup switch. I've replaced the bearings - it seems to turn freely - the fan is solid steel so heavy, but it does rotate freely. I've tried moving it from where I had it to another outlet. I don't have extensive experience with induction motors, but I am not aware of them simply "wearing out". I know the windings can burn out, but because of it's gradual decline, I don't think that's it. I have not yet tried rewiring it to 230V, but will try that soon. I suppose I could have replaced a bad capacitor with a new bad capacitor, but that seems unlikely. I suppose I should test the new ones. It definitely acts like it's the starter capacitor. I'm out of ideas and am hoping someone has some insight. Thanks.


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## TimPa (Jan 27, 2010)

an ac motor typically does not have 2 start capacitors, but rather one "start" capacitor (ranges: 430 - 516 mF, 110-330 VAC) and one "run" capacitor (ranges: 5-45 mF, 370-440 VAC). i got these ranges out of my motor book. replacement caps do have to go back into their respective positions in the circuit. polarity is not an issue on these.

i would recheck that you have correct replacements for the originals, and, they are in the proper location. also, since wiring has been disturbed, recheck that it is back in correct configuration.


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## bsandor (Feb 5, 2020)

Thanks, TimPa. I replaced the caps one at a time, so did not change them in the circuit. That makes sense about a start and run capacitor. The replacements are a match for the voltage and capacitance in each case.


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## HoytC (Dec 30, 2019)

bsandor-


There's a failure mode that, while rare on single phase motors, I've run into twice on dust collector motors.


Dust collectors are often subject to fairly short on-off cycles and at the same time have a high inertia load that prolongs the duration of the start current. This can cause excessive heating of the rotor conductors, softening the Aluminum they're made of. These conductors are connected by a shorting rings that are also Aluminum, cast into the rotor at the same time as the bars. There's a stress riser at the join of the two that can fail when the Aluminum is weakened by high temperature. When the connection to a bar is opened it no longer conducts current. That missing current has to be made up by increased current in the other bars. That causes more heating of those bars on subsequent starts leading to a cascade of failing joints.


This is especially rare on single phase motors because, under these conditions, the start capacitor usually fails long before the rotor does.


When you changed the bearings did you notice anything that looked odd on the rotor? Were there any loose pieces of Aluminum inside the motor housing?


Like I said, that's a rare failure mode. If it it were my motor I think I would want to convince myself that the centrifugal switch is actually working properly. Maybe attach a meter to the start capacitor terminals and make sure there's a solid voltage there when the motor is switched on.


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## TimPa (Jan 27, 2010)

bsandor said:


> Now it will not start at all - it always trips after a second or two.


so you went from frequent cb tripping, to not running at all - after part replacement. indicators are that: a bad part was installed, part installed incorrectly, or mis-wired. do you have a multimeter and know how to use it? have you tried spinning the motor when power is applied to "get it going"? be careful if the fan is installed, maybe use a stick. have you checked that the motor is getting 120vac (start switch ok)? if you are not familiar with electrical troubleshooting, please get help...


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