Do I Need A Magnetic Motor Starter?

[Susan_in_SF]

Hi Guys,
So, I was browsing Craigslist (very dangerous since I already have too much stuff) when I saw an ad for a magnetic motor starter. I didn't know anything about these devices, so I did some research online. I wanted to know if I needed a magnetic motor starter. After 20 minutes of reading and not getting an answer, I thought I'd turn to you "gentlemen," and any "ladies" out there.

As most of you guys already know, I am a measly renter working out of a 1 car garage. Have 2 outlets on different circuits in my garage. My washer and dryer are on a 120v 20 amp circuit (I have a gas dryer), and my garage ceiling outlet (the apt mgmt installed it for my garage door opener and light) is, I am guessing, 15 amp ( It is "community" electricity so I don't pay for using this outlet.

With using my metalworking machines, I can run my Bijur micro droplet coolant system and the air compressor off the 15 amp ceiling outlet while the machine is on my 20 amp outlet.

Well, having limited power in my garage has forced me to be creative while still keeping safety in mind.

I wish I never encountered Bill Pentz's website at: http://billpentz.com/woodworking/cyclone/

After reading his blog on the horrors of woodworking dust, a 1 hp dust collector just wouldn't do for me anymore.

However, with my garage's current electricity situation, I can only run one machine at a time (which is fine since I would be by myself), and the dust collector would have to be run off the 15 amp "community" outlet. However, the 110v, 15 amp circuit won't work for motors greater than 1 hp.

Ok, I realize that this site is for machinists, not woodworkers. However, this is the only site that I am an active member of. Plus, I also plan on building a separate dust collector for when I am grinding metal. I already have a 12 inch aluminum impeller for it. Did I mention Overkill is my middle name?

Going back to the Bill Pentz blog, he mentioned how ineffective a 1 or 1.5 hp dust collector actually is at getting those nasty little particles.

How would I be able to have a larger hp dust collector if all I have is a 15 amp outlet?

Well, this is where I tell you my plan, and this is where you get to judge if I am either really smart or really stupid.

**Warning** --super long story with probably too much detail (Crap, maybe I should have put this warning at the beginning of the post)

First of all, my lathes and mills can use a VFD as a phase converter, along with a step up transformer to run 3 phase 220v motors with variable speed. I read online that lathes and mills can get away with not using a rotary phase converter and can use a VFD instead since they just need to the converter to start the motor.

With dust collectors, on the other hand, they have to use a rotary phase converter due to running at full load, and need the converter continuously.

So, for the dust collector, I picked up (at a deal) a Quick 220 voltage converter off Craigslist. This gadget will take 2 non-GFCI 20 amp 110v outlets, and will create a 220v outlet. Since I am a renter, I can't be rewiring the place, lol.

I looked at my circuit options, and decided to use the 20amp circuits for the garbage disposal and for the dining room outlets. All I have to do is drill a hole from my storage closet wall to the garage on the other side to run the heavy gauge power cord. Then, should I move out, just spackle the hole up.

I could have tried to use my 3000 watt step up transformer, but just felt the Quick 220 was better for the rotary phase converter.

Then, after researching what size rotary phase converter I needed (taking into consideration that the converter/slave motor should be at least 50% larger than the motor running the machinery), I bought a 5hp rotary phase converter for $135 off an ebay guy who makes these as well as "kits".

I then picked up, off of ebay, a 5hp Baldor motor for $50, plus $50.03 shipping, and a 2hp Baldor motor off craigslist for $60.

Fyi, I have gotten incredible motor buys off of Ebay when I use the "best offer" option with sellers who are liquidators. I once bought a 2hp Baldor Reliance vector motor, with encoder attached, for $95 plus free shipping.

I feel that it doesn't hurt to offer these guys super low offers since they are eager to move their inventory, and they have access to much cheaper shipping rates than the regular Joe guy selling a motor that he no longer uses.

So, I think I did ok. The total cost of the 5hp rotary phase converter and 2 motors cost just under $300.

I plan on hooking up the Quick 220 outlet cord into the 5hp rotary phase converter.

I bought the 2hp Baldor motor since I felt 2hp was sufficient for my dust collector. I then read conflicting info online in regards to whether there is motor power loss with rotary phase converters. The 2hp and 5hp motors are TEFC. However, if I am going to have power loss, I can use my spare 3hp Baldor motor, but it is not TEFC. 3hp would be the absolute largest motor I can use with this setup.

Ok, now that I told you all this info, I will return to my original question:
Do I need a magnetic motor starter?

Thanks in advance for any advice/feedback/schooling you may have for me

Susan

 

[pstemari]

...So, for the dust collector, I picked up (at a deal) a Quick 220 voltage converter off Craigslist. This gadget will take 2 non-GFCI 20 amp 110v outlets, and will create a 220v outlet.

I'm rather suspicious of this gadget. The two outlets must be on opposite phases for it to work. The website says it's UL-listed and has interlocks to prevent problems, but I wouldn't trust that unless I verified the listing with UL.

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[Susan_in_SF]

I'm rather suspicious of this gadget. The two outlets must be on opposite phases for it to work. The website says it's UL-listed and has interlocks to prevent problems, but I wouldn't trust that unless I verified the listing with UL.

Sent from my Pixel XL using Tapatalk

Understood. I will later today do some research if anyone has had issues with this gadget.

 

[chips&more]

Time to move! Forget about buying a house. Just buy some land and put a GIANT quonset hut/airplane hangar on it! And they make VFD’s with 1ph 120v in with 3ph 240V out.

 

[JimDawson]

Susan, from what you describe it sounds like you are maxing out your available power now. I'm not excited about those 220v converter thingies, and that won't add to your power, but might give you 15 amps of 220V. Why do I say 15 amps? Because you would have to plug one cord into the 15 amp outlet and the other into the 20 amp outlet in order to get 220V. BUT.... This assumes that each of those outlets is on the opposite leg of the 220, if they are on the same leg then it won't work at all.

A 5 HP RPC, loaded, is going to draw about 23 amps of 220V, or about 46 amps at 110V Even with a 110-220 step up transformer at best you are only going to have about 10 amps available at 220V.

Bottom line is that you need more power. I would recommend moving out into the country somewhere with a nice big shop.

 

[ttabbal]

I don't know about the original question, but if you have a 220V outlet nearby for a clothing dryer, you can make an extension cord for it. I did that while renting a place that had an unused one due to having a gas dryer. Even if you have to share, dry clothes are overrated..

The 2 120V to one 220V adapters are safe, but you have to verify that they are on opposite phases. It's not difficult and the commercial units probably have simple detection systems to help you out. I've built adapters that go both ways. Nothing to it. A little common sense goes a long way with these sorts of things.

 

[Bi11Hudson]

You actually have several questions, as points of conversation. All in all, there is no good news. You have stretched your electrical service to about its' limits now. Going any further will require at least an electrical upgrade. As a renter, you know how far that would go. Like others have said, relocation is the best answer.

Now, to your basic question. A "motor starter" is simply a very large relay with the addition of a thermal protective circuit for the motor. I personally recommend a starter for some 3/4 HP motors that run a high(or continuous) duty cycle. That's both single and poly phase. At one(1) HP, that's any motor. My personal opinion, now. There are 5 HP motors that run off a disconnect but I don't approve in the slightest. A fire just waiting to happen. A burnt motor at best. Such devices are not sharable. One motor per starter. Period, non-negotiable.

There is one possibility here. You state you have a gas dryer. Look on the back wall for a "crowfoot" plug, behind or very near the dryer. If there is one, there is a source of 220-240 volts with 30 amp capacity. If it's there... ... That's your only out, unless, of course, you don't need the kitchen range. With a teenager in the house, I won't go there. I have pulled such shenanigans in the past, at remote office locations. But won't recommend it.

Your second question is about rotary phase converters. The first question would be "how many motors" will you run from it. If it's just the dust collector, no others, I have a suggestion for you. A rotary converter is simply a three (3) phase motor running with a few capacitors off of single phase power. Since the dust collector is run continuously, let it be its' own converter. That would cut down a bit on power usage too. A converter is sorta thirsy. There are many web sites on doing 3 phase from single conversion. I used to have it on my web site and removed it for liability reasons. It is(was) a corporate site and the insurance folks reduced my rate when I removed it.

The bottom line here is that, unless you have a dryer plug or tap into the range, it ain't gonna happen. At best, you will only trip breakers. At worst, the whole building will burn down. Don't go there. California has enough fires already. Dont start another.

Bill Hudson​

 

[ThinWoodsman]

Do you have access to the electrical panel for the garage? Hit the mains disconnect, add a 20-amp (or, hell, why not 50!) breaker, wire to a socket, claim ignorance when you move ("I recall the handyman elbow-deep oin the thing cursing, one day").

Much harder if you only have access to the apartment breaker, as it's going to be flush with the drywall so you'd have to punch a couple holes to run the wire.

And I agree with pstemari, device sounds a bit dodgy.

I would recommend moving out into the country somewhere with a nice big shop

Worked for me!

 

[markba633csi]

You may be in a part of San Francisco with really prehistoric wiring- maybe even going back to the earthquake
If you don't have a 220 volt stove or dryer outlet you are pretty limited in amperage
mark

 

[RockingJ]

If I hear of another great fire in S.F. I will know where it started! You are already running more that I would recommend on the existing wiring, don’t add more!

The use of a contactor to control motors allows the contacts in the contactor to take the power surge when the motor starts up. This way the circuit switch doesn’t arc across the contacts every time the circuit is energized or de-energized. The contactor has much larger contact points that can take the spark better.

Another thing is you should have a motor starter in the input circuit to the rotary phase converter, the motor starter is simply a contactor with an on/ off switch and overload protection. It also will shut off the circuit if there is a power loss. This prevents the RPC from restarting automatically when power is restored.



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