Profitt Technical Services
Site Map
Contact
Richard A. Profitt
95 Bramble Bush
Springboro, OH 45066

Ph: 937.748.1052
Cell: 513.465.1326

EMail:
Copyright
1999+ Profitt Technical Services

Web Management by:

Dear Mr. Wizard (Q&A)


Dear Mr. Wizard (Q&A).


---- Question: 0 ----

Deer Mr Whizerd

I open upa box to add an 3 phase motor start up gizmo an got zapped wif 220 votes even tho I test each arm to groun an got no votes watt happen?

R. Extracrispy

ACKME Widget Company
 

---- Answer: 0 ----

Assuming an arm = a short leg and the 3 phase 220VAC power came from the secondary of a step up or step down transformer, there may not be any direct difference to ground. The secondary of the transformer may have what is called "Floating Ground" or no ground at all and still be hot between phases.
 
 

---- Question: 1 ----
 
Dear Wiz,

We have an operator panel with a lot of 24 VDC Lamps. They seem only to last about 5 months. I'm replacing about 2 or 3 every week. There's no machine vibration and the power supply reads 24.5 volts. We are trapped into a continuous buying cycle. Should we sue the bulb manufacture or buy a lower voltage power supply?

Mr. D. Filament

Lightless panel company

 
---- Answer: 1 ----

With only a 10 to 20% drop in lumens, bulb life could be 10 to 20 times longer. Adjust the power supply down to 21 or 22 volts. If you can't change the supply volts the one EZ solution is to use voltage-dropping diodes on the common for all the pilot lights. Each silicon rectifier in series will drop the voltage feeding the bulbs by 0.4 volts.
 
 

---- Question: 2----

My Dear Mr. Wizard:

On March 21st of this year, at 6:57AM I was electrocuted by a 440 volt AC terminal I touched even though I tested zero volts between two power wires; one of which was only connected to that terminal. The shock only lasted 7.25 milliseconds because my jerking motion allowed my favorite Phillips to be welded between a terminal and the enclosure simultaneously blowing a 40 amp. Fuse. The short jolt of electricity coursing through my torso seems to have improved my language skills without any side effects except for my strange attraction to neon signs and a nagging feeling that the shock was only at 220. Why did this happen and what do I do now?

R. E.

The ACME Widget Co. Inc. Esq. Ltd.

P.S. I keep blowing 40 amp. fuses.

 
---- Answer: 2 ----

Branch circuit wiring may be the same phase and would test 0 volts between them yet both would be hot with respect to ground. Always test leg to leg to leg AND leg to ground.