40A Breaker For PM Dual Drum Sander?

[Derek Arita]

I posted this on another forum, but haven't heard from anyone that actually owns this machine, so I'm posting it here in the hope of hearing from some of you that own this 5 HP sander.
Anyone that owns the PM Dual Drum Sander might be able to help me out on this one. PM says that this machine will require at least a 40A breaker, if not a 50A. Seems this has been discussed in the past and I thought owners were using a 30A breaker with 10g wire. The tech tells me that the motor uses 23 - 30 amps full load and he did say that start up with a 5hp motor required a 40A breaker or excessive tripping of the breaker may occur. Any input from those who own this drum sander would be very helpful. I'd like to know what breaker size and wire size you're using. Thanks for the help.

[Charlie Plesums]

A 5 hp motor should run at under 30 amps, 240 volts, like you have been told. I have 4 machines with 5 hp motors in my shop, and the key is the load when they start. Saw, shaper, etc. start easy, so they peg the ammeter only briefly, and have never blown the 30 amp breaker. The bandsaw has monster wheels (52 pounds each), so it really is a heavy load when starting... the ammeter is pegged for several seconds on a 60 amp scale. I haven't blown the breaker yet, but I hear several people with similar saws have had to go to 40 amps, because of starting load.

Part of it may be related to line voltage. In our area, the voltage is high - one reading with a good meter was 245 volts. Motors like high voltage (within reason), so I am far less likely to have a problem than someone who only has 220 or 230 volts.

I don't have that drum sander, but anything you can do to reduce the starting load, or be sure you have full voltage under load (adequate wire size, no long runs, etc.) should help. Assuming your drum is heavy (like my bandsaw wheels are heavy), you are on the hairy edge with a 30 amp circuit.

[Ken Garlock]

I second Charlie's comments. My IR 5 hp compressor calls for a 40 amp circuit/breaker, but in 4 years running on a 30 amp circuit it has never popped a breaker or complained about starting.

Regarding startup of the sander, I would think that the sander will start under a no-load condition(no wood under the sanding heads.) With the no-load, the motor should quickly come up to speed, and most, if not all, breakers have a short delay built in to accommodate starting current surges.

[Cliff Rohrabacher]

Drum and belt sanders consume HUGE amounts of power.
The surface engagement is very large. The only way to overcome all the friction generated is with generous amounts of power.

A tablesaw has a little tiny area of cutter engagement by comparison.

If the PM specs require a 50A line you probably should provide it.

There aren't many things worse for an AC motor than under powering them except maybe flipping them into reverse while running.

[Mike Hollingsworth]

I had one of these hooked to a 30 amp beaker and it was fine.

mike

[Byron Trantham]

Drum and belt sanders consume HUGE amounts of power.
The surface engagement is very large. The only way to overcome all the friction generated is with generous amounts of power.

Boy I can second that. I bought PC belt sander and tried to use it with the auto-start feature of my Festool dust extractor. Nope, that doesn't work. I guess it handles about 9 amps max and I think the belt sander draws a lot more than that. Anyway, no dust extractor.

[Kirk (KC) Constable]

Lemme say this about that...

First place, PM should know what the electrical requirement is, and they should tell you...no guesswork.

I installed a 60 gallon IR compressor that called for a hard wired circuit. Naturally, I put a plug on it and wired up a 30A receptacle because it was simpler (to me). We had problems with that compressor right off (unrelated to that), and the VERY FIRST thing they asked was the size of the breaker and was it hard wired. If not what the instructions called for, they weren't sending anybody out. Period. If for no other reason than that, I've decided it's worth the $25 or however much more it costs to do what they tell you, even if you think it's overkill. They may be playing CYA, but you should be, too.

KC

[Steve Clardy]

I'm with KC. Do what PM tells you.

[Jeff Horton]

Ditto, you wanted expert advice. Whats better than the people to design and build it?