Suggestions for a dissconnect means. Dissconnecting motor from MCC via Plug ?

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milmat1

milmat1

"It Can't Do That !"
Location
Siler City, NC USA
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Controls Engineer
I have a project that contains a movable system. The system will be moved on two separate towed cars, on one car will be a generator and MCC cabinet, and a 10HP motor. on the second car a 125HP motor and a 15HP motor. All motors will be soft started.

Now the trick, During transport the two cars will be separated. So I need a means of connecting the 125HP motor and the 15HP motor to the MCC cabinet on the opposite car. It Must be field pluggable and easily removed for transport. As well as easily reconnected at the job site.

My concern is how to do this in a safe way that will insure someone doesn't accidently disconnect the running motors etc, or worse connect them under full load etc..

Anyone ever done anything like this before..?
 
milmat1 said:
I have a project that contains a movable system. The system will be moved on two separate towed cars, on one car will be a generator and MCC cabinet, and a 10HP motor. on the second car a 125HP motor and a 15HP motor. All motors will be soft started.

Now the trick, During transport the two cars will be separated. So I need a means of connecting the 125HP motor and the 15HP motor to the MCC cabinet on the opposite car. It Must be field pluggable and easily removed for transport. As well as easily reconnected at the job site.

My concern is how to do this in a safe way that will insure someone doesn't accidently disconnect the running motors etc, or worse connect them under full load etc..

Anyone ever done anything like this before..?
Click to expand...

See if this may help: http://www.meltric.com/index.html
 
Never used any but I think there are devices out there that have control circuit contacts in them and will not make those contacts until after the power contacts have been made - opposite for breaking connections.

Wiring controls with a momentary start contact/holding contact will prevent connecting under load (unless start button is held for some reason) but will still allow disconnection under load.
 
Pin & Sleeve

Pin & Sleeve

You don't say what voltage you are working with, but Pin and sleeve devices ($$$$$) is likely what you need for the connection / disconnect means with a proper disconnect / shutoff means before them.

Not sure you can do anything about someone plugging and unplugging while hot other than specify a person be trained on the proper procedure.
 
cpinetree said:
You don't say what voltage you are working with, but Pin and sleeve devices ($$$$$) is likely what you need for the connection / disconnect means with a proper disconnect / shutoff means before them.

Not sure you can do anything about someone plugging and unplugging while hot other than specify a person be trained on the proper procedure.
Click to expand...

The meltic product Texie and I posted is rated as a controller.
 
texie said:
See if this may help: http://www.meltric.com/index.html
Click to expand...
I think that is the product I had on my mind. Doesn't look like it interrupts any control circuit like I mentioned, but still gives you a safer environment for making/breaking under load then most other plug/receptacles.

kwired said:
Never used any but I think there are devices out there that have control circuit contacts in them and will not make those contacts until after the power contacts have been made - opposite for breaking connections.

Wiring controls with a momentary start contact/holding contact will prevent connecting under load (unless start button is held for some reason) but will still allow disconnection under load.
Click to expand...
 
Add my voice to the Meltric cheering section, I used those for years on portable crushing plants because, as my partner used to love to say, Fred Flnstone and Barney Rubble worked in a quarry, the guys that do now are their direct descendants, and no smarter. So we had used Arc-Tite plugs and receptacles for years, then switched to Hubbell because the color coding made it easier for them but eventually, Fred or Barney would pull a cord befor shutting down and although they were relatively safe, the cap and receptacle would be unusable. So we switched to Meltric and never had another problem, other than explaining the higher cost to the owners.

kwired said:
I think that is the product I had on my mind. Doesn't look like it interrupts any control circuit like I mentioned, but still gives you a safer environment for making/breaking under load then most other plug/receptacles.
Click to expand...
You can add what are called pilot control pins that disconnect before the main pins separate, but we found that it introduced a lot of voltage drop issues into the control circuits. The Meltric having the rating as a disconnect device is even better.
 
I don't work with equipment like this, but I am wondering is it possible/practical to install the disconnect means in an enclosure with a switch where the load is shut down when the cover is open?
 
I add my positive vote to the meltric, but, if I understood the video correctly, it has a 60HP max rating. Sounds like's Jraef's "pilot control device" might be needed for your 125 HP.
 
What about parallel connections.
I wonder if you can have some sort of interlock box that holds the pin and sleeve devices that you have to remove the control connection in order to pull the pin and sleeve typ Meltric
 
THANK YOU !!

THANK YOU !!

Thank you all !

I think I could use the Meltric style. And if needed I could have more contacts than I need and place jumpers across them to form an interlock. So if it would get unplugged I can kill the motors..

BTW It is 480 VAC
 
Barbqranch said:
I don't work with equipment like this, but I am wondering is it possible/practical to install the disconnect means in an enclosure with a switch where the load is shut down when the cover is open?
Click to expand...

We are likely talking pin and sleeve type of receptacle here. I suppose it is possible to somehow put receptacle inside an enclosure, and use a disconnecting switch that prevents opening the cover unless the disconnect is open, then the receptacle would be dead when inserting or removing the plug.

Might cost less to just go with the Meltric devices that have been in the discussion though.
 
Yeah, Getting more involved than I had really considered. This application is a portable crusher setup. Run from a 400KVA generator. It has one 125HP 480V 3PH Main motor and two conveyor motors. 10HP and 15HP. All motors are to be soft started.

Am I thinking right here, I envision a Disconnect enclosure w/panel. (Main disconnect enclosure with a fused disconnect.)
To enclose the controls and soft start units, contactors etc. Then the motor leads will exit the control panel with whatever means I decide on. Whether I place the point of disconnect at the cabinet, at the front of the second car or at each motor...
 
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