Oneida Smart Dust Collector on dedicated 20A circuit

[John Donofrio]

Quick question about a potential dust collector purchase.

Is anyone powering either the 2 or 3hp Oneida Smart Dust Collector on a 20A circuit? When the shop was built I pre-wired a dedicated 220V 20A circuit not realizing this would limit my dust collector choices. I know, my fault for not researching a little more about them at the time but the wire is in the wall and wouldn't be a simple task to upgrade to 10awg.

I asked Oneida if 20A would be sufficient (the manual recommends 30A) and their reply was to stick to the 30A recommendation which I understand due to liability issues. But they also added I might be able to "get by" with 20A if when connecting the collector to a small (<4") connection I open another port to allow more air flow.

Here are the amp draws from their web site:
2hp = 14A
3hp = 19A

These will vary though due to the VFD on these collectors. I'm pretty confident I could use the 2hp model but I'd really like to get the 3hp model and 19A is getting pretty close; I could see it popping the breaker when it ramps up on the smaller connections.

Any experience out there with this scenario?

Thanks in advance!

[Michael W. Clark]

I don't have this collector, but It's usually best bet to stick with the OEM's recommendations.

However, I'm not sure I understand their logic that it will draw less amps pulling more CFM (opening another gate)? There was a recent thread on CFM vs Amp draw. I assume this collector works off a VFD the speed is always maxed out to maximize amp draw (HP). If you connect a 2-1/4" hose to it, the max speed will likely be limited by the fan max safe speed or stable operating point and not the amp draw.

[Ole Anderson]

You don't want to draw 19 amps on a 20 amp circuit. I stick with the 80% rule although it doesn't strictly apply to motor loads.

[mike mcilroy]

Its not hard to run a new circuit and get the 3hp collector you want. Use the circuit thats already there for another machine in the future.

[John Donofrio]

Thanks for the reply guys.

At this point I'm not sure which route I'm gonna go. Probably leaning towards the 3hp with hope that it works but ready to add/upgrade circuit if it doesn't... As the saying goes, hope for the best but expect the worst.

Also haven't completely ruled out a non-VFD model, especially since the $ difference is stupid.

Thanks again.

[Len Rosenberg]

John, I just bought an Oneida 3 hp Smart Dust collector, although I have not hooked it up yet. The spec plate on the motor states that at 240 volts, the motor draws about 8 amps. I'm not well versed in things electrical, but doesn't that mean that a 240 volt, 20 amp circuit is completely adequate? I hope so because I just had an electrician run a 20 amp circuit just for this machine. I will be calling Oneida tomorrow and will let you know what I find out.
Regards,

Len

[David Kumm]

Remember the Smart runs a three phase motor with a vfd from a single phase source so the amp draw of the motor will be roughly doubled on the input side. The smart adjusts the speed of the impeller to pull more cfm when the pipe is small which in turn will increase the amp draw. Fix it right the first time and run the #10 wire. Reducing the effectiveness of the DC rather than fixing the wiring will be a regret forever. Hurt now and be done. Dave

[Len Rosenberg]

Thanks David. That is great information to have, but is news to me -- nowhere on Oneida's website does it state that the Smart is a three phase motor with a variable frequency drive. All it says is that the motor is variable speed. Perhaps the 3 phase + vvd is obvious to the electrically savvy, but I'm just a mere woodworker consumer. Also, the Oneida site specifies the following as the required "power supply: 208-240V single phase power. 50-60 hz. 19 Amps." Doesn't that mean that a 20 Amp 240v circuit is fine? Also, if the 8 amp draw is doubled, to 16 amps, isn't a 20 amp dedicated circuit enough to cover that draw? I appreciate your help.

Thanks,

Len

[Mike Chalmers]

No way a 3 HP single phase motor only draws 8 amps. My King 3 hp cyclone is rated to draw 18 amps.

Not an exact duplicate, but, I had a 18 amp 120V table saw. I had to install a 20 amp circuit breaker with delay built in before tripping. This allowed the circuit to go over 20 amps. with an ordinary 20 amp breaker, it was tripping it almost every time I turned it on.

[David Kumm]

Dust collector motors run harder than most of the machines in woodworking shops. If Oneida says 19 amps you want to give yourself some room and go with #10 wire. You could install the collector and check the amp draw on the input side with gates open and see how much it draws. If close to 19 amps, do yourself a favor and run some flex on the wall and convert to a 30 amp breaker. The vfd in the smart may soft start the impeller which reduces the start up draw so you might be OK with the 20 amp but you want to check the draw for sure. Dave

[John Donofrio]

@David K: Unfortunately I pre-wired the 20A circuit and as I said in the original post, it wouldn't be a simple task to upgrade to #10 unless I was willing to run a conduit on the wall. I'd really rather avoid that but I may not have a choice if I go with the 3hp smart.

@ Len R: I feel your (potential) pain since I really want the 3hp. Any idea when you might have the thing assembled and ready to test on the 20A circuit? My feeling is it will be OK unless it's connected to a single small port but that's just a guess at this point (but supported by the reply I got from Oneida).

[Rod Sheridan]

No way a 3 HP single phase motor only draws 8 amps. My King 3 hp cyclone is rated to draw 18 amps.

Not an exact duplicate, but, I had a 18 amp 120V table saw. I had to install a 20 amp circuit breaker with delay built in before tripping. This allowed the circuit to go over 20 amps. with an ordinary 20 amp breaker, it was tripping it almost every time I turned it on.

Yes the motor draws 8 amperes, 3 phase.

The VFD that runs it probably draws just over 16 amperes...........Rod.

[Chris Merriam]

For me, the one area I will never try to bend the rules is electrical wiring. It's just not worth risking your entire house and family's safety. Any book on electrical wiring will tell you not to exceed 80% of a circuit's capacity, so you should be running no more than 16amps on a 20amp circuit. Yes 30 amp is more expensive, the locking outlets and plugs alone are $22 each at the big box stores, but I'm happy to pay knowing I'm safe.

[Marty Tippin]

Run a new 10 ga circuit in conduit. Problem solved.

[Mike Chalmers]

For me, the one area I will never try to bend the rules is electrical wiring. It's just not worth risking your entire house and family's safety. Any book on electrical wiring will tell you not to exceed 80% of a circuit's capacity, so you should be running no more than 16amps on a 20amp circuit. Yes 30 amp is more expensive, the locking outlets and plugs alone are $22 each at the big box stores, but I'm happy to pay knowing I'm safe.

Locking outlets and plugs? Maybe for a generator.