Sometimes my heart aches for Electricians

Goody

Member
Join Date
Apr 2002
Location
Huddersfield W Yorks UK
Posts
1,081
Life can sometimes be horrible for normal installation electricians. Bosses just don't seem to know the difference between an electricain that rewires houses and installs power, to one that programs plc's and designs controls.

yesterday I was called to a factory (never been before) where they had called three different electrical companies to repair their machines.
The company was in desperate trouble. Two of the same type of machines had stopped working and had been off for a week. Production had ground to a halt at this bottleneck.

The two electricians I met there had been there 3 days solid and both had the look of total defeat in their eyes. The management were on their backs all the time and these poor lads were really up against it.
Not only that, there were no drawings or information of any kind to help them.

I plugged into the first plc (a mitsi FX1n 60) and saw almost immediately that a long 'run' line had one input missing.
I got them to work tracing the input wire to it's source while I plugged into the next machine (a Siemens S200)

Once again, I saw something that should be on that wasnt. The lads had been through the machine so thoughourly that when I said we need to trace wire No 522 - one of them knew where it was on the machine.
The first was a centrifugal switch that had jammed open as it was full of gunk and the second was a proxy that the signal wire had broken off but still looked connected.

All this took about half an hour to have them fully running again.

I was then embarrassed to witness these two good lads getting a real ticking off and being told their invoice would not be paid.

The irony was though, I wasnt treat with any deference. I had just done a normal job to them - and the other two were beneath contempt.

I did feel sorry for them but on the upside, they did look pleased to be leaving the place. :) :)
 
No, that would have been too easy. One had a light stack with one amber light flashing - it meant nothing to anyone. And the other had one green 'run' lamp that was not on.

They are basically automatic wet yarn spin-dryers that the operatives load and spin at the same time - One was a dettin - you can see it here

http://www.wotol.com/1-dettin-berta-24-hydroextractor/second-hand-machinery/prod_id/126832

The other although the same job was a different make
 
... Bosses just don't seem to know the difference between an electricain that rewires houses and installs power, to one that programs plc's and designs controls.

... :) :)

"Bosses" are bosses for many reasons... they were replaceable on the tools, they were good at bluffing and talking a good job, they were loud mouths who took the credit for their mate fixing the fault, they poo-pooed others' ideas then passed them off as their own later, etc...

"Bosses" from the production side of things seem to think that engineering came about overnight. They often view the chaos of the problem... and then the relief of a solution in place, but whilst they're in meetings about meetings they miss the heart-ache, struggle and skill of correcting the problem. They then want to know where to point at when the problem returns. Then, when a similar problem occurs they look good by recalling the location of the last fix. How good is that? :geek: Heroes.

We had one boss, a former chemical engineer, suggested we power three-phase machines via single-phase motor inverters!!! o_O

I love people watching!

"The more bosses I meet... the more I love my dogs!"

As L D[AR2,P#0.0] hinted towards... a window of opportunity to offer HMI interfacing for fault location, if not, you've proved your worth and they have your number!

regards
s.f
 
Did these machines have any MMI ?
That is what I was thinking too.
If the machine is complicated enough to have a PLC, then it should also have an HMI (*). And the HMI should have anough status displays and error messages to quickly pinpoint a defective sensor.
I think an HMI is mandatory, because the local electrician cannot pinpoint an error inside a PLC in the same way as he can by tracing regular wiring.

*: Many old machines dont have such advanced stuff. But then they should have been designed with som kind of simple error display. Just a number display for an error number, or one alarm = one alarm lamp.
 
Originally posted by JesperMP:

But then they should have been designed with som kind of simple error display.

Or simply a manual to tell someone what it means when the yellow light is on and what imput states are required to make it turn off.

One of the better manuals I saw in this regard was for a Dolci winder. It had a plc that controlled the winder transfer cycle. It had three or four pages listing every stage of the transfer sequence along with the state of every input and output for that stage. It became obvious fairly quickly what was holding the machine up.

Keith
 

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