Motor Connections- How Do You Do Yours?

[4GSR]

As the title says, "What method do you use for making your motor connections?" I'm refering to promarly for 1 HP and larger motors, single and 3-phase, excluding stepper motors or any motors that have it's own kind of connectors.

The method I use, taught by my dad, is to use ring terminals on all motor leads and line wires coming into the pecker head. Connections are bolted with stainless or brass screws and nuts. Cover the connection with Scotch 2242 rubber electrical tape. Last a layer of Scotch 33 or 88 vinyl electrical tape.

Who wants to go next?

 

[John Hasler]

Ring terminals or compression fittings. I prefer shrink-tube boots to rubber tape though I will use the tape. The vinyl tape is a waste of time: it always falls off.

 

[Ulma Doctor]

80% of the OEM, NEMA motors in the industry i service use wire nuts to 10 hp, the IDEC motors are ring terminated in the motor .
ring terminals and brass screws and electrical tape exclusively for motors manufactured by the Hobart Corporation.

+1 on 3M tape or any other 3M product for that matter!

 

[Tony Wells]

Same as John. Gets kind of crowded to do a decent tape job, but lots of that is done. Whoever invented shrink tubing deserves a pat on the back. I have a bit left from some lithium battery packs I built for Tensor, high temperature stuff with a good shrink ratio. I will hate to have to replace it. I recall it being pretty costly.

 

[JimDawson]

Like Mike, I use wire nuts up to 10HP on NEMA motors. I normally don't tape wire nutted connections. Above that the wire sizes are really too big for wire nuts, so I use split nuts, rubber tape, then vinyl tape.

Never thought of using shrink tube, but I like the idea!

I don't like ring terminals/bolts, because that adds another layer(s) of connection that can fail over time, especially in wet/outdoor locations. I have had connections fail on IEC motors due to terminals failing. Those get replaced with wire nuts or split nuts.

In corrosive locations, think sewage treatment plant (ammonia and copper don't get along well), the connections get filled with anti-corrosion goo.

 

[Bob Korves]

Old school. Start watching at 17:30. Stan is a true pro millwright and knows how to do things right. If Stan wired my own deep space probe, I would be happy to live in it...
This is only one method of wiring, but it is solid and proven.

 

[mksj]

On anything above 24V, I usually use ring terminals on the motor end, crimped, then the tips are wick soldered and then fusible shrink tubing over the crimp/wire and if used, the shield foil. If the motor has a terminal block then it is a direct connect, you can use some sealant/film over the terminals if in a corrosive environment. In the marine environment for battery terminals and such with copper wire, soldering fills any void area and protects the wires from corrosion in the crimp. Do not let the solder flow down the wire past the crimp. The fusible shrink tubing protects the crimp/insulation and secures the wire. A bit of overkill especially when using an industrial crimper, the wire will fail before the wire pulls out of the crimp. If the motor does not have a terminal block, I prefer to use a separate terminal block as shown, I mount it to the housing if there is enough room in the connection box. These type of terminal blocks have a snap in cover, which prevents a terminal being shorted/touched. On the power end, I either will use ring terminals or locking spades, they are easier to get into some terminals and are hard to pull out. I use a touch of blue Locktite on the motor terminals or a screw connection exposed to vibration.

Wire nuts are common, I have seen corrosion and oxidation occur over time, when used in these type of connections I wrap them with electrical tape to minimize moisture and possible loosing. If it is in a hostile environment, you can get the waterproof wire nuts, and then tape.

 

[Tony Wells]

There exists also a gel filled shrink tubing for harsh environments. I had forgotten about that. Pretty handy stuff too.

 

[dieselshadow]

On bigger motors I use split-bolts, wrap vinyl tape inside out for a few wraps, then wrap in rubber tape, then a final layer of vinyl tape. The fist layer of vinyl tape sticky side out really helps when you need to unwire the motor. You can easily re-use the split-nut because the tape will come off clean. A quick swipe with a fresh razor blade and it all comes off.

 

[jim18655]

For those that tape their connections - start the tape on the wire then flip it over and put several layers on sticky side out. Now the rubber tape and follow with vinyl to hold the rubber. When you have undo the connection just cut through the layers and the tape will come right off like a rubber boot.