Troubleshooting Jobs

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Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Read War and Peace-- that will give you something to do....:lol:

I got a call from a guy who had 3 electricians come to his house who told him the only way to do the job he wanted done was to open the walls.

The room was on the second floor of a 3 story finish apt. There was one switch and a ceiling fan -- one switch leg- The light came on with the fan but he wanted to put a track light on the ceiling about 2 feet off the wall. He was okay if the light on the fan and the track came on together but he didn't want the fan to operate at the same time.

I thought it was a no brainer- took us about an hour -- no drywall repair. What did I do?
 

Besoeker3

Senior Member
Location
UK
Occupation
Retired Electrical Engineer
Post some troubleshooting jobs or questions so I have somethings to read.

I was called to site one Saturday morning because of a "thumping" noise coming from a DC variable speed drive. It sounded like a misfire. It wasn't.
Can you guess what it was?
 

kwired

Electron manager
Location
NE Nebraska
Read War and Peace-- that will give you something to do....:lol:

I got a call from a guy who had 3 electricians come to his house who told him the only way to do the job he wanted done was to open the walls.

The room was on the second floor of a 3 story finish apt. There was one switch and a ceiling fan -- one switch leg- The light came on with the fan but he wanted to put a track light on the ceiling about 2 feet off the wall. He was okay if the light on the fan and the track came on together but he didn't want the fan to operate at the same time.

I thought it was a no brainer- took us about an hour -- no drywall repair. What did I do?
If there was power in the box at all times, you used the pull chain switch on the fan to control the fan and the switch leg to control the light(s).

If there wasn't originally power in the box at all times, maybe some advanced control (wired or wireless) and associated relay.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Read War and Peace-- that will give you something to do....:lol:

I got a call from a guy who had 3 electricians come to his house who told him the only way to do the job he wanted done was to open the walls.

The room was on the second floor of a 3 story finish apt. There was one switch and a ceiling fan -- one switch leg- The light came on with the fan but he wanted to put a track light on the ceiling about 2 feet off the wall. He was okay if the light on the fan and the track came on together but he didn't want the fan to operate at the same time.

I thought it was a no brainer- took us about an hour -- no drywall repair. What did I do?

That's easy. ​​​​​​You slid some white insulation on the EGC and used it as the neutral, used the black as always hot for the fan, and colored the original white with red to use as the switched leg. Then you tapped the white and red to feed the track with a fished cable.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
That's easy. ​​​​​​You slid some white insulation on the EGC and used it as the neutral, used the black as always hot for the fan, and colored the original white with red to use as the switched leg. Then you tapped the white and red to feed the track with a fished cable.

Nay, I don't do those thing.....Everything is legit. No feed in the ceiling just a switched leg. Kwired had the right idea.
 

Besoeker3

Senior Member
Location
UK
Occupation
Retired Electrical Engineer
An AC motor?
DC drives and motors. About 200kW beasts.

It was during the test cycle of a couple of winches. These were run back to back in that one was winching in the steel rope, the other was winching out or rendering as it is called. The same rope.
So one driving while the other was in regenerative mode. When the rope came to the end the roles were reversed. This cycle was over a period of several days.

The thumping noise did sound like a misfire so I put my 'scope across the drive current feedback. All was well, perfectly balanced current pulses. The problem was mechanical.

The transmission from motor to winch drum was an internally toothed belt. Morse belts they were called. Now and again, one of the belts jumped a tooth on the winch drum pulley. That's what made the thump.

An aside. I was called out by the mechanical designer of the winches. I, the electrical designer, ended up solving a mechanical problem.
Can be a funny old world at times.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Are we correct that the feed is to the switch box, not the ceiling box, and only two conductors between them?

That is correct

Don't read further if you don't want to know









Very simple. Went to Lowes and bought The electronic switch and fan receiver. Mounted the switch in the switch box and the receiver in the fan canopy. We fished a wire in the same stud space as the fan over to the track and wired that 14/2 to the neutral and the hot to the receiver switch leg.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
... I, the electrical designer, ended up solving a mechanical problem.
Can be a funny old world at times.
Yes, I believe it, I can't count the times that has happened for me too.

One such story was on some overhead bridge cranes where two 200ft. bridges could be locked together to become like one 400ft. bridge. The mechanism for doing that was a hydraulically driven set of large tapered steel pins that extended from the end of one bridge into sockets on the other. I was there to troubleshoot the PLCs and VFDs, but was pulled into a situation wherein the pin extension was not working. It had a small drive motor for the hydraulics that reversed to extend or retract the pins, no springs or valves. I forced the I/O on the PLC to make the motor turn on in both Fwd and Rev, which it did fine, but no action on the pins. Everyone was blaming the PLC even though I proved that it was working correctly. I then solved the problem in two minutes.

What did I do? All necessary info has been provided here.
 
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