I picked up some '70s era GE NEMA 1 magnetic contactors, NOS, military
spares. They have overload relays that accept heater inserts and are
adjustable within ±15% of nominal via a thumbwheel. Clearly the heater
inserts are literally just that - they heat the inside of the overload
relay. Beyond that, though, I'm stumped. I'm trying to figure out how
these overload relays work. Anyone know? The overload relay number is
CR124 if that helps.

Grant

--
Posted via a free Usenet account from http://www.teranews.com

http://www.google.com/url?sa=t&ct=re...wd1_FcldMO-zkA

On 2008-01-26, Grant Erwin wrote:
I picked up some '70s era GE NEMA 1 magnetic contactors, NOS, military
spares. They have overload relays that accept heater inserts and are
adjustable within ±15% of nominal via a thumbwheel. Clearly the heater
inserts are literally just that - they heat the inside of the overload
relay. Beyond that, though, I'm stumped. I'm trying to figure out how
these overload relays work. Anyone know? The overload relay number is
CR124 if that helps.

Grant

On Jan 26, 11:42*am, Grant Erwin wrote:
I picked up some '70s era GE NEMA 1 magnetic contactors, NOS, military
spares. They have overload relays that accept heater inserts and are
adjustable within ±15% of nominal via a thumbwheel. Clearly the heater
inserts are literally just that - they heat the inside of the overload
relay. Beyond that, though, I'm stumped. I'm trying to figure out how
these overload relays work. Anyone know? The overload relay number is
CR124 if that helps.

Grant

--
Posted via a free Usenet account fromhttp://www.teranews.com

A contactor and an overload relay together are called a starter.

The heaters in the overload relay are interchangeable (to match
the current requirements of the circuit), and are intended to
heat either a bi-metalic element or a meltable metalic compound
(later models may be fully electronic) which allows an internal
switch (normally used to carry current through the contactor coil)
to open which breaks the holding curcuit and allows the contactor
points to seperate.

dennis
in nca

Ah. Bimetallic strip. Makes sense. Doesn't explain how the thumbwheel works,
but gives me a general idea.

Grant

Ignoramus17333 wrote:

http://www.google.com/url?sa=t&ct=re...wd1_FcldMO-zkA

On 2008-01-26, Grant Erwin wrote:

I picked up some '70s era GE NEMA 1 magnetic contactors, NOS, military
spares. They have overload relays that accept heater inserts and are
adjustable within ±15% of nominal via a thumbwheel. Clearly the heater
inserts are literally just that - they heat the inside of the overload
relay. Beyond that, though, I'm stumped. I'm trying to figure out how
these overload relays work. Anyone know? The overload relay number is
CR124 if that helps.

Grant


--
Posted via a free Usenet account from http://www.teranews.com

On 2008-01-26, Grant Erwin wrote:
Ah. Bimetallic strip. Makes sense. Doesn't explain how the thumbwheel works,
but gives me a general idea.

probably adjusts tension on the strip

i

Grant

Ignoramus17333 wrote:

http://www.google.com/url?sa=t&ct=re...wd1_FcldMO-zkA

On 2008-01-26, Grant Erwin wrote:

I picked up some '70s era GE NEMA 1 magnetic contactors, NOS, military
spares. They have overload relays that accept heater inserts and are
adjustable within ±15% of nominal via a thumbwheel. Clearly the heater
inserts are literally just that - they heat the inside of the overload
relay. Beyond that, though, I'm stumped. I'm trying to figure out how
these overload relays work. Anyone know? The overload relay number is
CR124 if that helps.

Grant

On Jan 26, 11:42*am, Grant Erwin wrote:
I picked up some '70s era GE NEMA 1 magnetic contactors, NOS, military
spares. They have overload relays that accept heater inserts and are
adjustable within ±15% of nominal via a thumbwheel. Clearly the heater
inserts are literally just that - they heat the inside of the overload
relay. Beyond that, though, I'm stumped. I'm trying to figure out how
these overload relays work. Anyone know? The overload relay number is
CR124 if that helps.

Grant

--
Posted via a free Usenet account fromhttp://www.teranews.com

A little latching bar sits on the thumb wheel to hole the points
closed...
When the strip heats up from to much current it releases the thumb
wheel letting it spin letting the latch fall off the wheel letting the
points come open...

On Sat, 26 Jan 2008 14:08:21 -0600, Ignoramus17333
wrote:

On 2008-01-26, Grant Erwin wrote:
Ah. Bimetallic strip. Makes sense. Doesn't explain how the thumbwheel works,
but gives me a general idea.

probably adjusts tension on the strip

Correct. More tension, faster trip.

Gunner


i

Grant

Ignoramus17333 wrote:

http://www.google.com/url?sa=t&ct=re...wd1_FcldMO-zkA

On 2008-01-26, Grant Erwin wrote:

I picked up some '70s era GE NEMA 1 magnetic contactors, NOS, military
spares. They have overload relays that accept heater inserts and are
adjustable within ±15% of nominal via a thumbwheel. Clearly the heater
inserts are literally just that - they heat the inside of the overload
relay. Beyond that, though, I'm stumped. I'm trying to figure out how
these overload relays work. Anyone know? The overload relay number is
CR124 if that helps.

Grant