Do you leave your D/C running ???

[Rick Peek]

Well,I broke down and ordered an Oneida v3000. Should be here this
week. My question is...do you leave your D/C running the whole
time you are in the shop? I read that the motors don't like being
turned on & off to often, but the thought of listening to it constantly
turns me off a little. I need to listen to my country music while
working.

[Chris Padilla]

I turn mine off and on many times throughout the weekend. I dunno if my motor likes it or not but it still runs so....

I'm with you, too noisy to leave it on all the time. If I could put it outside, I might feel differently.

[Dewey Torres]

Put this remote on a key chain and clip it to your workshop apron or belt loop. After a day or 2 in the shop with it, it will become second nature.

http://www.amazon.com/Rockler-Dust-C...1890364&sr=8-3

[Robert Parrish]

I have that remote and it works great! I only turn on my DC when I turn a specific machine.

[Maurice Ungaro]

The info from Oneida states that you should not turn that motor on & off more than 6 times per hour. You'll get used to it.

[Jim Eller]

My 3HP Gorilla says no more that five times in one hour.

That's what is says, that's what I do.

I usually believe the manufactures know as much about their equipment as I do

[Dewey Torres]

Going out on a limb here and I will probably pay for it dearly but aren’t those motors similar to table saw motors (just with a plenum air fan attached)?

I can’t imagine instructions that would come with a table saw telling you not to turn the motor on and off x times per hour…or any of the tools I have with electric motors for that matter.

[Jerry Olexa]

I turn on only when needed. My Jet air cleaner clears the ambient air on a remote timer when I'm not there

[Dan Friedrichs]

I'm with you, Dewey. Maybe they think the ideal thing is x times per hour, but I can't see how the motor would care.

[Dewey Torres]

I'm with you, Dewey. Maybe they think the ideal thing is x times per hour, but I can't see how the motor would care.

I know.... I am sure they had a reason but I just question the reason.

Shampoo instructions tell you to wash rinse and repeat!!! Who does that?

Now we all know that one is to sell more shampoo so it surly doesn't apply. I was just making the point that the manufactures recommendations are not always to make the tool last longer. There may be something I am not aware of but...

Like my band saw: I think it has a VERY similar motor as my DC. Maybe I should go run and check that. Ah what the heck, we are talking Oneida here so my findings will not apply.

[Tom Veatch]

...aren’t those motors similar to table saw motors (just with a plenum air fan attached)?....

I'm with you, Dewey. Maybe they think the ideal thing is x times per hour, but I can't see how the motor would care.

The motors are similar in that they are usually both induction motors. The difference is that the startup load on a DC motor with a high inertia blower wheel is much higher than that on a table saw motor with a low inertia saw blade. Therefore the time to reach full speed and drop the amperage in the motor to the much lower running current from the high startup current is much less in the table saw than in the DC.

The heat generated in the motor is a direct function of the amperage flowing through the motor. The high amperage, high heat input, startup phase of a DC motor lasts appreciably longer in a DC than in a table saw due to the higher startup load. This causes the DC motor to heat more during startup than the table saw motor.

High temperature damages the insulation on the wire in the motor coils. Therefore the potential for damaging heat buildup in the DC motor from frequent on/off cycles is much higher than in a table saw. When the motor is running at its design speed, the amperage draw is somewhere around 15% to 25% of the startup amperage, so heat is generated at a rate that allows it to dissipate before temperatures reach damaging levels.

Hence the recommendations of the manufacturers to limit the number of start cycles. This allows the motor to cool between the blasts of heat generated by the high amperage start up current.

Of course this all assumes the motor is operating within its load and environment design specifications.

To accommodate this, I installed a variable time delay in the circuit that energizes the coil in the contactor which switches my cyclone motor. When the tool shuts down, the cyclone continues to run for 5 to 6 minutes before it shuts down. There is also a manual override so I can manually shut the cyclone down prior to the end of the time delay if I know I won't be needing it for an extended time.

[Dave Verstraete]

Rick
I'd be taking a different thought on this one. Country music or DC "music" HMMMM...I'm not sure which I like better!

[Jim Becker]

The whole time? No. But I'll go for a period of time bouncing between machines sometimes, just adjusting the gates in use.

[Dan Friedrichs]

Tom,

I did consider that - I'm not sure I buy that the I^2R heating losses are significant enough to damage the enamel on the windings, though. It certainly makes sense, but it would take a LOT of heat to damage anything, and running the motor continuously will also generate heat, so maybe the manufacturer has decided that running the motor continuously makes as much heat as turning it on 5 or 6 times an hour. I reluctantly suppose that it's possible, but still feel that the amount of heat generated would have to be awfully large to actually pose any risk.

My intuitive feeling would be not to turn the thing on, say, 15 times an hour if you're working outside in 100F weather. But otherwise, this is probably not something worth worrying about.

Dan

[Tom Veatch]

...My intuitive feeling would be not to turn the thing on, say, 15 times an hour if you're working outside in 100F weather. But otherwise, this is probably not something worth worrying about.

Dan

Dan, you may well be right. I've never had the ambition to test or measure the heat loads on my electric motors but figured that in the absence of specific reasons to disregard mfg. recommendations the better part of valor would be to adhere to them. In a prior life as a design engineer, I never specified limiting recommendations without some technically justifiable reason for doing so. Of course by the time it was in the customer's hands, there's no telling what stickers, placards, and/or other "lawyer-speak" had been applied.