Test Bench Power Block Plug Headache

Hubbell makes several small wiring devices specifically for this type of application.

The 250V rated (6-X) series of straight blade plugs & receptacles are the same physical size as a standard extension cord.

(6-15) => 15 amps

(6-20) => 20 amps

The part numbers begin with HBLxxxxx. such as PLUG, HBL566C+,RECEPTACLE, HBL5662, and CONNECTOR, HBL5669C+

All are offered in hospital grade as well as weather resistant & waterproof.

A visit to Hubbell.com website will allow you to view the selection and make a choice of which devices you need.

They have many products, and I couldn't find anything small enough for what I want. Do you know a particular product they make that might be suitable?

I want something smaller than a standard U.S. plug due to the quantity I need and a desire to keep the assembly small.

Drew K

Check eBay. I did a search for AC plugs and came up with a lot of twist lok and other used or out of box plugs and they looked to be in good condition.

Here are my search results

Maybe save you some dough?

Just an idea.....

The link below is what I found for the first assembly, and is great for D.C. testing, but when I power it with 110 V I get a potential on the ring of the jack when the motor is running. And if I use 220 V I get a potential all the time.

I am using my first assembly right now with 220 V. It is working fine and is actually safer than what I was presented with by the previous design (daisy chained quick connect terminals that are left sitting on the shelf when one motor fails).

I would like to find something with the same ease of use but safe and insulated for A.C current.
Amazon Link

Drew K

Whatever you end up with, I would definitely do a continuity check with an ohmmeter to make sure both leads are isolated from anything external before applying power. Just sayin'.

Here is something you might want to consider. I developed this for a test panel to avoid having to apply plugs to the motor cable:

Harting connector

Pricey!

You need for USA 220VAC operation are only the two HOT legs of the incoming single phase and safety ground. You do not need neutral. (It is physically placed in the middle of the single phase for 120VAC usage only)....

You need 3 connections for 220VAC in the USA, each end of the phase and the ground for safety only.

If there is a potential between neutral and ground, is it within code allowances?... It should not have anything to do with a 220VAC motor, probably to do with 120VAC loads on the same system. I assume that the motor casing is properly grounded? But of course, NOT to the neutral! Even though at some point Neutral and ground are connected, you should not be repeating that at any other point......

In Europe, only one hot end of a phase is called "phase", as the other is connected as Neutral, and at some point before that to ground. There is 220VAC between phase and neutral. But it has little to do with US domestic supply.

I hope this helps.

Is this what you want? You clip 2 or 3 wires from your motor or other appliance into the block and close the lid to apply the power.

How many motors will you be testing at one time?

How many connects,disconnects per day?

What is the ampere demand for each motor?

Most plugs are not designed for continous connect-disconnect service.

More information on the application would help.

Let's see how many pictures I can load from my phone

Ok, I wasn't going to type much from my phone so the top picture shows the top of the box with timer, counter and switch. If you look carefully you will see how I am plugged into the 220 V with clips going to a 220 V plug lead.

*Please no lectures on safety* This is so much safer than what I am replacing and I am not done yet. I will cut the end off of the 110 plug so I can use the adjustable DC power supply for this unit.

The second photo shows the motors. They assemble the laminates and wind the coils on site. It is designed to turn the gearbox and stop with a locked rotor and hold without overheating until released. Locked rotor and running amps are monitored and some have thermal breakers in the windings of the motor.

What I want to find is a good plug that is as easy to use as the ones shown here but will be shielded to allow A.C. current.

Drew K

Isolation transformer?

The neutral wire is not needed in such an arrangement, so its potential to ground is irrelevant.

But I am using the neutral as my second black on the 220, and on the grey box pictured the neutral is connected to what should be the negative in a D.C. plug. So when a load is connected you can read a potential between the neutral and another ground. (test it out if you don't believe me :-) I had to)

Drew K

I can only say that you have made a mistake in thinking by attaching anything that should run at 220 volts to neutral! (naturally, in the USA! In Europe you would NEED to use it of course!).

That is what is confusing the whole situation. This unneeded connection to neutral!!

Problem solved.

I alluded to this in one of my previous posts as well....Post #9, where I posted the following:-

You need for USA 220VAC operation are only the two HOT legs of the incoming single phase and safety ground. You do not need neutral. (It is physically placed in the middle of the single phase for 120VAC usage only)....

To be certain, how about making a sketch for us all here with labeling please?

Thanks in advance.....

As pictured above, you see the inside of the box. Of the two plug leads going through the right hand side the top one is connected to the 220 V outlet. If you read the potential to ground from the black or the white you will find 110 V, read between the two and you get 220 V. The load is between the two and as I understand it one phase is leading the other so you get 220 V AC.

The motors rated at 220 V are running at normal speed and temperature so I think my set-up is correct.

The other plug lead is powering the 110 V solenoid, counter and timer and is wired standard 110.

Drew K

Another failure in thinking about USA electrics, that many have because so many talk of 2 phase power wrongly. So you are not alone....

The US 220 volt are simply one phase, that is why they are apparently at 180° to each other.

The neutral is simply a center tap, which means phase to neutral is around 115 VAC and phase end to phase end is 220 VAC.

In the USA, only a single phase is brought into domestic premises....

It seems that Edison is to blame:-

Edison introduced split-phase 110/220 distribution in 1883 primarily as a way to save on copper, but lamps remained 110 in this system, with two lamps connected in series between the two rails separated by 220 volts. The addition of a "neutral" conductor between allowed for one lamp to burn out without the other going out, and established the split-phase system we still use today.

OK?

I don't know if this is the same as what you mean, but the link below is how I understand USA 220 Voltage.

http://www.nojolt.com/Understanding_240_volt_circuits.shtml

I have only recently started learning wiring and electronics here in the states. I didn't do much more than automotive 12 volt wiring back in England.

Drew K

Its not quite written as clearly as it could have been, but I can see no obvious glaring faults.....I am assuming that the code mentioned is also accurate!

I can't tell exactly from the photos,but it looks like you are using the Green wire for ground,to get 110 volts.

If so,it is very wrong.The green is a chassis ground,not a neutral.

You must have a 3 conductor cord with ground (4 total conductors,one of them Green) to carry 240volt/120volt ac.

The cord should have 1 Red,1 Black, and 1 White and a Green wire.

The White is the Neutral,the Green is the Chassis Ground.

DO NOT CONFUSE GROUND WITH NEUTRAL-THEY ARE NOT THE SAME,even though

they may be bonded together at the main panel.This is the only place they should be

joined together.

If the inside panel is fed by an outside main panel,it is called a sub-fed panel,and the

bonding strap or bar must be disconnected at the sub-fed panel,and bonded only at

the main panel.

The Red and Black are the hot wires.

The White wire must go all the way back to the neutral bar on the main panel,via 4

prong cord to a 4 prong receptacle.

The Green wire is EXCLUSIVELY used for CHASSIS Grounding,not for normal current carrying.

If you use this Green for neutral,you are feeding power to every grounded receptacle in the building and could cause a difference in potential at some point,and present a shock hazard.

There is much confusion about the Grounding(green) conductor and the Grounded

Neutral conductor,even within the trade professionals so don't feel bad.

No, I am not using the green for anything. The entire rig is plastic and the motors are not grounded while testing. Perhaps I will set up a ground bar later and ground the motors directly to that, but there is nothing in the power box to ground so I just cut the green wire.

Right now for the 220, I am using the black and white as the two hots. Check out the link to the 220 volt explanation I posted earlier.

Drew K

I am working on it, but the mission must go on as I make improvements. I still have two shelves still using the daisy chain method

I will get a long copper bar, or grounding rod and connect that to either the mains ground or another grounding point.

Drew K

So if the shaded pole motor winding goes "grounded" to chassis you would not know

during testing,except for getting shocked when touching the motor?

Real smooth move there, EX Lax.

Not needed. If the connections are correct, there will be two hot legs 180deg out of phase, and a ground connection to ensure safety.

If in doubt, consult a qualified Electrician.

GA

What!?!? I think this is a very safe build...so much safer than what it is replacing. The previous engineer had almost no practical experience with wiring and had just daisy chained motors on a two strand red and black with blade or spade style quick connectors. When a motor failed he would take it off and wrap electric tape on the exposed connectors...I found several burn marks on those connectors.

Besides, like I said, I want this one to be for the D.C. motors and with no better options from here I will probably use shielded connectors (like below) for the A.C. motors.

Molex Sabre™

Drew K

You are comparing with something you have not told us all about.....not that something even worse should even be considered!!

Its like saying I got ONLY electrocuted for a very short time, not killed!!! The short time being better of course!!!

May I remind you, the aim when working with mains is not even to get a shock or cause a fire....

May I recommend a GFCI/ELCB breaker before this unit, still painful, but usually not terminal!!

I fail to understand how this will be used to test DC motors, that escapes me......

For DC motors I will cut the plug off and wire directly to the D.C. power supply. So far, I only got buzzed by one leg of the old set-up while working on the new. The old set up does not have any indicator that it is live and I shorted the solenoid with one hand.

What are your concerns with the box that I built. To give a brief description, on the top is the illuminated power switch that opens both the 110 V power and whatever is connected to the test circuit (currently 220 V). The timer controls the solenoid (I have been considering a solid state one but they fail in the closed position instead of the manual ones failing open). The counter is connected to the solenoid and counts the number of cycles. From the inside picture, you see the switch assembly on the top left, the large block of the timer n the middle top and on the bottom, the blue is the solenoid, the front bottom is the terminal block that distributes power to the individual sockets.

Drew K

The important parts of my posts you simply ignore.......

You could simplify the circuit by using the 220 volts as designed.

Carry the neutral into the box.

Use the 2 hots (1 Red,1 Black) for 220vac,and one hot to neutral(White) to power all of the 110 volt circuitry.

Carry the Green to a designated lug on the motor frame,which is required by UL

regulations to get their approval and seal.

Only one cord needed.

Simple.

You are not using the "neutral" (White) as a hot conductor.

You should apply Black or Red tape to this wire to indicate it is a hot wire.

(Tape color overrides wire color.)

It is used as the 2nd leg of the 220 VAC.

You do not have a real neutral in your system,as shown,except coming from the other 110 volt cord.

That is why you get 110 volts to the White,or Ground(green) of the 110 volt supply measured from the ring of your connector.

You should,according the the NEC have a GREEN(Grounding) conductor on the

motor,grounded to a "Green" designated screw.

Of course,that is by code,and you apparently don't care about that.

GA

You wrote:-

Of course,that is by code,and you apparently don't care about that.

Very true words, that could actually kill him!!

He does not even appear to need a "Megger" to check the motors before testing either, to give at least SOME indication of the state of the insulation......

Holy Shxt! You guys have become axxholes. What happened to this place. Management changes and suddenly you start attacking long time participants looking for advice on how to improve a dangerous condition at work!?!?

Fxck YOU. If this is how you want to help me I want the new oppressive overlords to ban me for this harsh comment.

Not once have I stated an intent to disregard regulations. I have stated that I do plan on installing a grounding system, but first things first. The first most important thing I NEED to do is replace the system I found that has daisy chained, un-insulated quick connectors with no ground.

Drew K

You are the one continually arguing against doing a proper job.

You are the one who does not understand the need for a safe grounding system as a first.

You do not want to use an RCD or similar.

You are the one who asked us, we did not "invite" you to ask us.

It remains apparent to most of us here that you are big know-all, who knows absolutely nothing useful, and even less about mains electricity!

I am gone because your stupidity and prevaricating has simply got annoying.

But do put some money on one side for your funeral expenses, with your attitude and knowledge, sooner rather than later....

Goodbye!

Big Brave AP.

I do not argue against doing a proper job, I am getting the mission accomplished while working up to a 'proper job'. I understand the risks of electric current as much as any of you. I take adequate precautions the the best of my ability; but you show me one experienced electrician who has not been buzzed and I show you a liar or a very lucky person.

Go ahead, make this personal, show your intellect by calling me a know-it-all who knows nothing useful. Check my record of good answers...(and go ahead and try to take them away) and you will see that I am very knowledgeable in many fields.

Don't worry, I served my native country in the military; my funeral expenses are paid for with my service...after all, we all die but many of us never really live.

//signed//

Drew K

"... we did not "invite" you to ask us" - please do not use the word "us" when posting anonymously. You do not speak for me.

I am not anonymous, and you shouldn't be (if you have a backbone).

LOL!!!

Is he still here?

Now that we have run the gambit of pedantic debate over my process does anyone have anything productive to add that is actually on the topic of finding a good plug for my purpose?

Drew K

If you Google the following companies, they will give you a better idea of what to look for locally. McMaster Carr, Grainger, MSC.

I have not checked MSC yet, but the locals here already looked in McMaster and Grainger.

Thanks for the advice, I will look in MSC.

Drew K