The other was a small base station which had its power input connections
designed by Mechanical engineers.
-----------------------

I wouldn't blame the mechanical engineers. I'd blame the engineering manager
who let mechanical engineers design an electrical interface, and then
apparently didn't design-review it.

Joe
W3JDR


"Steve N." wrote in message
...

"Highland Ham" wrote in message
...
I knew that I already had two phases in the guest room.
A couple of cheap extension cords was all it took, with one blade of a
"three prong adaprer" inserted into each hot side of each extension.
Guest
220 in 5 minutes!

I'd feel ok drawing 8A this way, but you shouldn't try this at
home...I'm a
professional. (:-)

Linears should have either
1- both 110 and 220 internal wiring options, or
2- just 220

But 120 is is a real stretch.
======================
Steve , Tnx for providing the 'full' picture.
Assuming a 67 percent efficiency (am I too pessimistic?) a legal RF
power amp would need 1.5*1500 = 2250 W (say overall maximum of 2400W)
which at 220 V means 12 Amperes.
So, a shack without 220 -234 V power supply would need a dedicated
supply from the switchboard .

Here in the UK we do have 115V industrial power tools,which need to be
used with a 230/115V (usually portable) safety transformer with the
secondary having an earthed centre tap ,such that in the event of a
'fault' personnel is exposed to a (peak) voltage not exceeding 1.4*58 =
81V which is considered sufficiently low to prevent electrocution.

The nominal domestic supply voltage within EU countries has now been
'normalised' to 230V ,meaning that (within a voltage band) the same
equipment can be used in all the countries.
Before , the UK had 240V and continental countries 220V . This often
meant that for example an (clothing) iron for 220 V had a very limited
life when used in Britain .
The voltage at my place (rural area) is nowadays usually 236-237 V
,whereas earlier it was up to 250 V or sometimes even higher.

Frank GM0CSZ / KN6WH



In the cell phone base business, everything (almost) runs off battery
systems.
There were two cases where Development Engineers not knowing about our
mains
system, where developing products never before run off the mains.
In one, the presence of "both" 120 and 240 was causing some spike
absorbers,
designed for 120 systems, to pop from the 240.

The other was a small base station which had its power input connections
designed by Mechanical engineers. It came to my test group without the
power cord connected to the black (protorype) "barrier terminal strip".
One
of the Develpoment Engineers called another for the connections and made
them. It was plugged in, but wouldn't work. Several Engineers started
checking and discuvered that the serial port on the control laptop had
been
fried. Several of us put our noses to the connector and could smell the
burned components on the unit. We also noticed that the heat sink wasn't
getting warm. I and several Engineers put our hands on the case to test
this.
Note: In the US, we have a third wire in all outlets which, though it is
the same as the common or neutral (basically also ground or no potential)
side, it is used to connect to any exposed metal parts. The purpose it
to
divert any hahazzardous shorts to ground and blow a breaker or fuse rather
than harming someone. We were focused on finding the cause. Several of
us
worked trying to analyxe the failure and found the serial interface of the
unit has fried as well as the lap top serial port.
Findings:
The HOT of the 120 ( instead of the safety ground connection) was
connected
to the chassis. This placed the outside of the (as yet unpainted) housing
at 120 VAC relative to all other grounded equipment in the room!
I was one of several who put his nose up to that hole to smell burnt
comopnents. I was one who felt the unit for heat build up.

It hit me half way home. Needledd to say, I gave the Mechanical and
Electrical Engineers a lecture on mains principles.

73, Steve, K9DCI