probably stupid electrical question (commercial electric): Off-topic discussion forum: Grassroots Motorsports Magazine

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Jan. 24, 2012 11:39 a.m. alex SuperDork

I got a great deal on a big '70s French fork mixer for my bread business, and I can't find any electrical specs on it. Can you tell anything by the type of plug it uses? (Told ya it's a dumb question.) I'm primarily worried about it being 3 phase, which would not be insurmountable, but a pain in the ass.

It's one of these 4 prong males (ignore the female side of the adapter in this picture):

Does that tell me anything, or will I need to dig into the body of the mixer and see if I can find some specs on the motor?
Jan. 24, 2012 11:42 a.m. Dr. Hess SuperDork

Looks to be a standard single phase 220V twist lock plug to me.

hash include std_disclaimer.h (I ain't a professional electrician.)
Jan. 24, 2012 12:27 p.m. Mazdax605 Dork

Looks to be a 30amp 250 volt twist lock plug to me. Not a three-phase from what I see there,but more than likely a 250v with a neutral,and of course the ground. The end of the plug in the pic there should have some markings on it that state the voltage,and amperage. Just have a look at it.

Of course if that is just a hotlinked pic then you are sort of out of luck because many of these twist locks look very similar, but are indeed different. Who knows how it is wired in the end of the cord cap as well. Sometimes people use a plug that has extra blades that aren't needed,but the plug works just fine. My bet is the motor has some markings on it somewhere. You may have to remove a cover or two to see it, but I bet it is on there somewhere.
Jan. 24, 2012 1:21 p.m. cwh SuperDork

There will be a cover plate over where the wires are connected into the machine. BUT, I would try real hard to find some kind of a hook-up diagram on line. Bad thing to get wires crossed up accidentally. Smoke, flames, stuff like that.
Jan. 24, 2012 1:55 p.m. alex SuperDork

Mazdax605 wrote:

My bet is the motor has some markings on it somewhere. You may have to remove a cover or two to see it, but I bet it is on there somewhere.

I think you're right. My Google-fu isn't helping me on this. Tomorrow, I'll have to schlep back out to the storage facility where I'm stashing it for now.
Jan. 24, 2012 2:02 p.m. alfadriver SuperDork

This is a used device here in the US/Canada? Should be able to run, at least. I'm with cwh in that there should be a "boiler plate" somewhere.
Jan. 24, 2012 2:12 p.m. alex SuperDork

This one has been used in the states, yeah. They're pretty rare over here otherwise.

I'll have to pop some panels off tomorrow and poke around. I didn't see a spec plate on quick, casual inspection, but I'd be really surprised if there wasn't one somewhere, at the very least on the motor itself.

If anybody's curious, the contraption looks something like this, though my model has some slight differences.

It's big and Gallic, so I'm thinking of calling it André (The Giant).
Jan. 24, 2012 3:31 p.m. Ian F SuperDork

cwh wrote:

There will be a cover plate over where the wires are connected into the machine. BUT, I would try real hard to find some kind of a hook-up diagram on line. Bad thing to get wires crossed up accidentally. Smoke, flames, stuff like that.

+1.

There should be name plate on the motor itself that will indicate the voltage and phase.

Most commercial-grade, floor-standing mixers I've circuited over the past 15+ years were 3-phase. Unless there is a light on the machine, it would be uncommon for neutral to be required.

However, if it is a 3-phase motor, all is not lost. Google single-three phase Variable Speed Drives. The internal circuitry can take a 1-phase input and output 3-phase. One example: http://www.dealerselectric.com/mfg-subcat-item.asp?cID=28&scID=165&mID=-1
Jan. 24, 2012 4:44 p.m. motomoron HalfDork
(Edit - I read Ian F's reply above after I wrote this. My bad)

The plug itself should have a NEMA # on it somewhere, from which you can obtain the corresponding socket. One X factor is that it could be 3 phase. There were plugs like that on both the lathe and mill I recently obtained - both of which use 220V 3phase power.

If it's 3 phase there are 4 options for how to cope:
- The commercial space where you'll be using this implement of potential personal dismemberment (IPPD for short) already has 220/440 3 phase power. In which case, set up a machine shop while you're at it. Home shop types fear teh 3 phase.
- Buy a static phase converter - the cheapest option if you don't have 3 phase. These synthesize the 3rd leg, but you'll only have 2/3 the rated HP.
- Buy a variable frequency drive (VFD) - costs more than a static phase converter, adds a lot of functionality, like infinitely variable speed, soft start/braking. Can be a bit of a pain to program initially.
- Buy a rotary phase converter - A big motor that gets fed 220/single phase and spits out 220/3phase. Needs a magnetic starter, kind of big, undeniably cool.
I'd planned on using VFDs 'til I found a big 'ol rotary while I was packing up the shop I bought.
Jan. 24, 2012 4:48 p.m. alex SuperDork

Excellent information. Thanks.

I'm going to crawl around in the car hauler (where this beast is still strapped down) in storage tomorrow. If I don't brain myself on the roof standing up too fast and bleed out in the privacy of a rural metal building, I'll let you guys help me decipher what I find.
Jan. 24, 2012 5:02 p.m. Giant Purple Snorklewacker SuperDork

One of the euro "gotcha" issues with equipment that comes up even if it is a single phase system is that it will have everything inside designed to be driven with a 50hz frequency and you will be providing 60hz.

If this machine requires tight control of speed/torque for the application that can be a direct factor - if it is a straight relationship to the motor - it is a 20% increase in speed. If it is not - then you may find that the motor controller uses a V/f calculation to control it and need to calibrate it. The V/f ratio will drop so the current draw will remain the same - wiring size and everything will be OK but things like current limiting relays and so on that use a bimetal heat or rely on freq for timing will all be a little bit batE36 M3.

I used to work in a shop that ran Danish made printing presses. If accuracy matters - get a freq converter and save yourself a zillion little things that are "just not right".

Also - if it has start caps - they won't work as well, which will greatly increase the load at motor start - which can trip current limiters. If it seems like the motor is trying to sink the entire building's electrical supply - get a bigger cap.
Jan. 24, 2012 5:51 p.m. alex SuperDork

I sincerely hope I won't have to learn what all means. But thanks nonetheless.
Jan. 25, 2012 4:04 p.m. alex SuperDork

My poking today revealed disappointingly little. The chassis of the mixer is missing two access/cover plates (one for the motor and one for the belt), and I'm guessing one of those had the specs on it, but it's long gone. I also couldn't find anything on the motor itself, since only one side is visible, and the rest is hidden in the body of the mixer.

What may be of help, however, is what I found on the plug itself. It is indeed a 4 prong twist-lock, and this is written on it:

HBL2721
30A 3Ø 250VAC

What, if anything, can we glean from that information?
Jan. 25, 2012 5:35 p.m. SVreX SuperDork

3 phase, 30 amp, 250 volt.

But the plug could be used on a single phase unit and work properly.
Jan. 25, 2012 5:44 p.m. SVreX SuperDork

Try removing the cover on the "peckerhead" (yes, that's the right name) that is, the cover where the electrical connections are made to the motor. It's where the wire comes out. Wiring diagram sometimes on the back of the cover.

You could also try removing the housing of the motor- sometimes on the back.

I'd also try pulling the coverplate on that large switch panel, though if there is a wiring diagram there it is more likely to be more complicated, giving variable speed and control wiring diagrams.

Motor wiring diagrams are usually VERY simplistic- sometimes looking like a simple game of tic tac toe. They may not even look like a wiring diagram.
Jan. 25, 2012 5:54 p.m. Kendall_Jones HalfDork

In addition, trace where the power cable goes into the box and look for a switch or fuseblock. Usually single phase has 2 wires/fuses & a ground, 3 phase will have 3 fuses (or 3 pole switch).

You could also unscrew that twist lock plug & see if there are 3 wires (single phase) or 4 (3 phase). Chances are its 3 phase - That looks like quite an apparatus, and using 3 phase power lowers the overall amps.

Kendall
Jan. 25, 2012 6:25 p.m. Mazdax605 Dork

Kendall_Jones wrote:

In addition, trace where the power cable goes into the box and look for a switch or fuseblock. Usually single phase has 2 wires/fuses & a ground, 3 phase will have 3 fuses (or 3 pole switch).

You could also unscrew that twist lock plug & see if there are 3 wires (single phase) or 4 (3 phase). Chances are its 3 phase - That looks like quite an apparatus, and using 3 phase power lowers the overall amps.

Kendall

You can have 4-wires and be single phase with a neutral for possible a light or other 120v piece on the apparatus. Just because you have 4 wires doesn't always mean 3-phase. My bet is this baby is three-phase though.
Jan. 25, 2012 6:36 p.m. Kendall_Jones HalfDork

In reply to Mazdax605:

However very unlikely with a 3 phase plug (they make twist locks with a center neutral pin right?). Each shop is different (I've seen lots of places use the same twist lock for single & 3 phase just to keep it simple). You just hope that whomever originally wired it used the right plug for the job.

KJ
Jan. 25, 2012 7:51 p.m. alex SuperDork

Likely adding to the complexity of this guessing game we're playing is that this thing was probably originally wired for French electricity. So we've gotta translate through the silly accent.
Jan. 25, 2012 9:29 p.m. Ian F SuperDork

"French" electricity isn't much different, just usually a different voltage (higher) and a different frequency (50 Hz vs. 60 Hz here).

The fact is has a NEMA plug on it could mean one of two things: 1. Somebody already installed a US-voltage motor and it's just a matter of plugging it in and going to work. 2. Somebody slapped a plug on it, discovered it won't work on US voltage, and that's why they sold it... Hopefully it's the former.

While it's not impossible, I would be very surprised if it' not 3-phase...
Jan. 25, 2012 9:58 p.m. alex SuperDork

Ian F wrote:

Somebody slapped a plug on it, discovered it won't work on US voltage, and that's why they sold it...

I do know this thing has been in service in the states, so I know it works somehow. But I bought it from colleagues of colleagues of colleagues of colleagues, so they're not exactly a phone call away.

I got a screaming deal on this thing, so I have to take this extra hassle with a grain of salt.