Need Help - New Shop Electrical Missbehaving

[eaglesplsh]

We just had new electrical service installed in our shop to support our new ShopBot and we're having a problem with it...

When ever the dust collector is turned on, lights through out the shop and house dim and other electric tools - like our router tables slow down momentarily while the dust collector motor comes up to speed.

I know this isn't a board for electricians, but I figured someone might have dealt with something similar in their shop... our electrician seems to be stumped and I'd love to have some advice for him when he comes back to finish the job tomorrow.

The new service is 100 amps, with a separate 110 volt/20 amp breaker for the dust collector. All electric in the garage is new, coming through this 100 amp sub panel, which connects directly to the main house panel (200 amp service total.)

The dust collector is rated at 11 amps for 110 voltage.

The lights that dim/motors that slow down are on completely different circuit breakers.

The electrician tells me that he checked all the connections in the 100 amp sub panel and main panel and that nothing was lose or unexpected.

Thanks - Russ

[dlcw]

What kind of dust collector is it? Have you tried plugging it into another outlet on another circuit? Can you plug it into an outlet on the house circuit to maybe isolate whether it is in the 100amp sub-panel or system wide? If it still bogs everything down, you might have a faulty motor on the dust collector that is drawing way to much current.

Don
www.diamondlakewoodworks.com (http://www.diamondlakewoodworks.com)

[gc3]

200 amps total with a 100 amp sub panel...still only 200 amps TOTAL for your house and shop. A 11amp/110V induction motor will draw close to 3 times it's rated running amps when starting...so with loads at the house plus loads in the shop...what is left for the induction motor to start up? It will cost, but maybe a dedicated shop service is what you need.


Gene Crain
www.plantasymaderas.com (http://www.plantasymaderas.com)

[Gary Campbell]

Russ...
It sounds like you have a low voltage condition caused by the start up load of the DC. You should check the actual voltage during those conditions to give the electrician a better path to the solution. Make sure that you check across the 240 volt legs and each 110V leg to ground or neutral.

Things to check:
Actual line voltage available at meter.
Distance from main to garage subpanel, paying special attention to wire size. A few more $ for oversized wire is cheap insurance.
That the house isnt using the majority of the 200 total amps, which would cause the undervoltage condition.
Check the phase balance in both the home and garage panels. You may have them phase divided numerically, but not load balanced.
You should have all heavy load items, such as the dust collector, on 240V. This will allow much more efficiant operation and much less line loss.
Make sure that you have 4 wires to the subpanel.
Place the breakers for heavier, or consistant load items next to each other or in an even/odd to split use of the 240V buss.
What is the wire type and size used to power the shop equipment? 12 is the minimum, 10 is better. Stranded in conduit is better than romex type house wire.

FYI: We use a separate 100A subpanel in our shop just for the ShopBot. (out of our total 400A)
Gary

[gene]

You need to call your power supplier to get a bigger transformer put on the pole where your power comes in at. My shop was doing the same thing. I asked a meeter reader and he refered me to the power co electrical engineer and thats what they came up with . Give them a call and they should be able to help.

[frank134]

first how far is it from your house panel to your shop panel? what size wire did you use? Is it large enought for the voltage drop? Check to make sure the screw on the lug to your panel are real thigh. also the one on the 100 amp breaker are thght. check to make sure the breaker is seated tight in the panel. I am am electrical and this sound like a lose feeder wire or and under size wire or and bad neutral. the probelm might be in your main panel at the house. that were I would look first. what tell me this is the light in the house are dim. If you can't find it their. call your power company. you could had a bad neutral at your pole. check the voltage at you main panel and see if it drop when you trun thing on at your shop.


hope this help.

[eaglesplsh]

Thanks all - good questions and equally good suggestions... I'll print this all out and show it to my electrician tomorrow, so keep 'em coming!
Boy is he going to be surprised!

The dust collector is a 1 1/2 HP Jet / ShopFox (DC-1100 I believe.) I wouldn't categorize it as an industrial sized unit meant for a large commercial shop, though it does a good job for our needs.

I never really thought about how everything is attached together in the breaker box and could interact. I assumed that breakers kind of isolate their loads from one another. I deal more with chip level electronics, not the heavy duty stuff.

This symptom showed earlier today, when the only things turned on were the flickering/dimming lights in the one room that I was testing, the dust collector, and our refrigerator. We don't have AC, furnace was off, hot H20 is propane, all other tools/lights/computers/TV etc. were off. We certainly shouldn't be hitting the 100 or 200 amp limits.

Distance from the Garage to the main panel is about 40 feet. I'm not sure what size wire they used underground/to wire the circuits, but I'm sure it's the code spec, as they're having a state inspection done once the work is complete. Weather the code spec is enough may be a question mark - I'm not qualified to judge.

I'll drag the dust collector around to other outlets/circuits, including inside the house, and see if that shows anything. Funny how this is the first thing I'd do for a broken lamp, but last thing I'd think to do for a dust collector that seems to work great.

I'm sure the electrician will want to look for lose connections again. They tightened everything once today. Then we can try all the volt meter readings...

Never a dull moment!

Russ

[tmerrill]

I have that same dust collector and it can be wired for 220 volt. I would recommend doing that and putting it on it's own 220v circuit. This will reduce running current and starting current and also balance the load across the two legs of the sub-panel.

Your electrician should be capable of doing this.

Tim

[butch]

I have the same setup. 200 amp service with 100 amp to the shop. I have the Grizzly 1 1/2 horse dust collector, but I have it wired for 220/20amp. I do not have any flicker or brown-out when starting the dust collector. For that matter, I have started the dust collector and the planner or sander at the same time, while running the ShopBot with no problems. These are all 220v items but still I am not draining the 100amp service to the point I notice any problems.

You shouldn't be having problems.

Another area you might want to check is that the start circuit (capacitor and contacts) are working correctly on the dust collector.

Butch

[donchapman]

Ditto on what Butch just said since I too have the same setup and no problems so long as I run the dust collector on 220.

[eaglesplsh]

When I looked at the sticker on the dust collector yesterday, I saw that it had a 220v 5.5 amp rating as well as the 110v 11 amp rating. This was the first time I had noticed it.

Is there a simple/non-destructive way to rewire a dust collector motor/starter/etc. from 110v to 220v?

I had just assumed that they sold 2 units - a 110v version and a 220v version, and that they used the same sticker/motor on both versions. I figured that I was stuck with what I had and never thought about switching it over...

Thanks again for all the input.

Now the hunt begins for the old DC manual.


Russ

[wberminio]

Russ

First congrats on your machine!
On the 220v conversion- open up the connection box
by the motor and you should find a diagram for the conversion.
It's a simple matter of moving a few wires.

Erminio

[donchapman]

Erminio is right. It's very simple and can be done on any of your other workshop motors that have both a 110 and a 220 volt rating on the motor, which is usually true of most capacitor start induction motors of 1 HP or more.
Make the switch to 220 on your other workshop motors such as table saw, planer, sander, etc. and you'll find they run more efficiently both because it's 220 and because you pull half as many amps and have less voltage drop in the wires that supply your tools. The smaller amp load is why your house lights will probably no longer dim (or insignificantly) when you start your dust collector.

[tmerrill]

Russ,

Unless this electrician is your brother-in-law or someone else you can't easily say goodbye to, I would find one that has experience with commerical electric wiring and motors. The electrician should have been recommending this stuff to you yesterday and not just checking and re-checking for loose wires.

Sounds like this one has just done simple residential wiring for too long.

Tim

[tmerrill]

If you can't find your manual, go here and see if they have your model number, then download it:

http://www.wmhtoolgroup.com/Media.aspx?nav=Manuals

I've seen too many times where a manufacturer changes motor brands and doesn't update the manual. If your manual doesn't agree with the diagram Erminio told you about under the connection box cover, go by the diagram on the motor.

If you are uncomfortable doing this, by all means have the electrician do it. Electricity isn't too forgiving.

Tim

[eaglesplsh]

Thanks again to everyone - the ShopBot forum never ceases to amaze me! How did we ever get through life without the internet?

All seems to be working properly now - I'll summarize what we found/did for anyone who runs into a similar problem and finds themselves reading this thread down the road:

We checked voltage everywhere - coming into the house, coming from the house into the 100 amp sub panel, coming out at the socket - all was what it should be.

The number of wires to the sub panel/wire gauge running to the outlets also matched recommendations listed above.

When run on 110v the start up current spiked at 33 amps! Running load was down around 7.5 amps. I don't know if that means there's a problem with the starter or not. Anyone know how to test the starter to find out? The label lists 11 amps, which I had assumed was the expected start up draw. If that's actually the running draw then Gene's post above indicates that 33 amps might actually be normal for start up.

We switched the motor over to 220v, which was just as easy as everyone said it would be (diagram was inside the starter box, just two wires changed.)

When run on 220v the start up current spikes momentarily at 20+ amps. Voltage between the legs, etc. all stays where it should. My router table RPM (on a separate circuit) doesn't drop in an audible way and the shop lights look good.

So... it's back to assembling the bot. Hope to have some interesting things to share in the Show and Tell section soon.

Russ

[tmerrill]

Starting current is almost impossible to calculate (predict) exactly using formulas due to all the variables. The rule of thumb is 4 to 6 times running current and you are in that range.

Like others have said, if you have a power tool that can be converted to 220v and have the room in your sub-panel, it's to your benefit to change over.

Happy you got this one behind you.

[tkovacs]

I agree with all the postings above but there is one more thing you should check. First - I am NOT an electrician - but I believe that with the situation you describe the new box should have it's own separate grounding rod (outside in the ground) for the neutral buss bar. Also all boxes have a strap that normally connects the two grounding bus bars in the box and the ground wires (the bare or green wires) and the neutral wires (white) can be connected to either buss bar, but in a sub-panel like you describe this strap should be removed and all the neutral wires should be connected to one buss bar (the one that is also attached to the grounding rod) and the ground wires should all be connected to the other.

Here is one reference that describes this situation:

http://www.thathomesite.com/faq/lists/wiring/2005015726007600.html

I also have a 1 1/2 HP grizzly DC wired for 220. In fact all my big machines have been rewired for 220 - it makes a big difference.

[tmerrill]

If the sub-panel is in the same building as the main panel then a separate ground rod(s) are not required. If the sub-panel is in a detached building, then they are. This can be subject to local code, so it is best to check.

In Russ's case hopefully the electrician got this right.

[Gary Campbell]

Terry...
Shouldnt the neutrals be connected the isolated buss bar and the grounds connected to the equipment ground, case and the ground rods?
Gary

[butch]

Here's how I check a start circuit.
Usually the contacts are burned and sometimes welded closed. Usually this is an indication the capacitor is out. If the capacitor is out, there is sometimes oil or burn/smoke spots from the capacitor in the box.
What I do is call the manufactor and ask them. They will walk you through checking. I just went through this with a Grizzly 15" sander with 5hp motor. Still pulling too many amps when not under load, but too hard to pull out and check again.
But it apears to me you fixed the problem.
Butch

[gene]

A subfeed panel should have an isolated ground to keep curent from back feeding thru them

[frank134]

the only time the ground and neutrals are tied together is at the main panel. the code requires a separate isolated neutral and a ground wire but does not require a groung rod at the second panel even if it at another building ( but i put three in a triangular formation at my shop). It is just a good idea and it will give you that extra safety. gary knows the link to the guy that sells the vac motor. He also sells what they call a soft start for whole house or shop. It is around $300, I think. It not only saves energy and money but will reduce start up current on every machine. I figure mine paid for itself in 6 months. This unit is good for single phase only. sorry I thought you wrote in your first post, that no matter what you turn on, the lights dim.

[tkovacs]

Gary -
Yes, I believe you are correct - my mistake.
Terry

[eaglesplsh]

Just to clarify, in case anyone reading this is thinking about buying the same dust collector for their shop...

There is no sign of starter damage/failure - nothing burnt, melted, etc. I'm convinced that the DC is not defective. It just needs a lot of power and should be run on 220v like many others have attested to in this thread.

After starting the unit several times today while cleaning up, I noticed that the 220v wired motor seems to come up to speed about 2x faster than what I used to see with 110v wiring - I'm sure that's related to the 110v lights dimming problem.

While this is the only DC I've ever owned and I can't compare it to others, it does a good job and I'd recommend it to others who have a small shop with 1-2 tools creating dust at the same time.

[terryd]

You have two 110 volt 100 amp legs coming into the shop and more than likely you have two or three circuits ( 15 amps) for lights etc which eats up 45 amps then you fire up the collector
which is 20 amps running , usually more during start up. Now your pulling 65 +/- amps from one leg hence the dimming... What you need to do is to balance your panel... Most smart electricians will fill one bank then drop to the next level.Since most panels are offset when it comes to breakers, two breakers next to each other will be drawing from alternate legs and thus the panel is balanced. I have seen shops where they have brown out conditions which distroys motors only drawing 100 amps on 200 amp service... If the electrician doesnt understand panel balance then youhad better find a new one. As a further note this also applies if one is drawing his power from a sub panel fed from the dwelling..If your stove , drier and hot water tank are all on the same leg as you dust collector connection in the shop then there will not ever be enough current to prevent this if your cooking bathing and botting at the same time.

[curtiss]

dumb questions below...

Does running a dust collector or router on 220 cost less to operate than 110? My DC pulls about 6 amps on 110.

Does a 1 HP three phase motor cost less to operate than a 1 HP single phase ?

The difference between a neutral and a ground is.... ?? I would suppose there is a link to all this info somewhere...

thanx

[dlcw]

Check out this website:

http://www.csgnetwork.com/energycostcalc.html

Should answer your question.

Don
www.diamondlakewoodworks.com (http://www.diamondlakewoodworks.com)

[dana_swift]

Curtis-

Q: Does running a dust collector or router on 220 cost less to operate than 110? My DC pulls about 6 amps on 110.

A: Effectively the same. The kilowatts consumed is the the same, because the current is lower at 220, the voltage loss (drop) in the wires is lower so it is very very slightly more efficient.

Q: Does a 1 HP three phase motor cost less to operate than a 1 HP single phase?

A: Usually the answer is "sorta" yes. Assuming you have 3 phase power available. Again if you consume the same number of kilowatts with both motors the charge is the same. Some power companies place premiums on 3 phase, and another premium on "power factor". 3 phase motors are generally more efficient per horsepower, that is where the "sorta" answer comes from.

Q: The difference between a neutral and a ground is.... ?? I would suppose there is a link to all this info somewhere...

A: Imagine your shopbot were to be installed and operated in an aircraft. At best the skin of the aircraft is called "ground", but it is not usable as an electrical power conductor, a neutral wire is run to carry the current for the half of the circuit that is at "skin voltage". It is not possible to be connected to "ground" during flight.

In earth based power systems one conductor is connected to the earth at the meter, it still carries 100% of the current of a 110v circuit. That is the "neutral" wire. Just like the neutral wire in an aircraft. Then another wire is run for safety which should carry no current at all. (Similar to the aircraft skin) It is also run to the ground rod, that wire is "ground".

Most systems are wired with two 110v circuits that share the common conductor "neutral", and have two separate "hot" lines. The voltage between the two hot lines is either 220 (usually), or 208 depending on the transformer configuration. The currents in the two 110v circuits tends to cancel the current in the neutral conductor so it stays at a much lower value than the "hot" lines.

In case of a fault, the ground line has to be able to conduct enough power to cause the circuit breaker to trip without exposing a (accidentally connected) human to a potentially lethal voltage.

That is condensing a lot of electrical engineering into an abbreviated explanation.

Hope that makes enough sense.

D

[gc3]

...wiring is not a hobby, call a qualified electrician...are good words to go by.



Gene Crain
www.plantasymaderas.com (http://www.plantasymaderas.com)