Odd power switch in Metcal Volume Fume extractor

[Dave]

I have a large Metcal "System 1000" Volume Fume extractor with a bad power
switch. I've never seen any switch like it. The printing on the switch
says:

"Weber Unimat / WTNL 22-551"

It's rated 15A/120V, 16A/240V. It's a 22mm x 43mm (13/16" x 1-5/8") amber
illuminated rocker switch with a relay built in. There are 5 quick
disconnect terminals: 2 relay primaries (P1 and P2), and 3 contacts (3 4
5). The switch was disconnected when I got the unit, so I don't know how
the two wires from the outlet and the two wires to the motor were
attached; but connecting live & neutral from the wall to the two wires to
the motor (bypassing the switch) allows the unit to run.

1) Any idea what the relay is all about? I imagine that it must have been
put there for a reason.

2) Does anyone have any schematics or repair/wiring info for this or
similar Metcal units?

3) Any idea how to replace the switch? What harm would result from just
using a regular DPST Rocker?

Thanks,

Dave

 

[Mike Harrison]

I have a large Metcal "System 1000" Volume Fume extractor with a bad power
switch. I've never seen any switch like it. The printing on the switch
says:

"Weber Unimat / WTNL 22-551"

It's rated 15A/120V, 16A/240V. It's a 22mm x 43mm (13/16" x 1-5/8") amber
illuminated rocker switch with a relay built in. There are 5 quick
disconnect terminals: 2 relay primaries (P1 and P2), and 3 contacts (3 4
5). The switch was disconnected when I got the unit, so I don't know how
the two wires from the outlet and the two wires to the motor were
attached; but connecting live & neutral from the wall to the two wires to
the motor (bypassing the switch) allows the unit to run.

1) Any idea what the relay is all about? I imagine that it must have been
put there for a reason.

2) Does anyone have any schematics or repair/wiring info for this or
similar Metcal units?

3) Any idea how to replace the switch? What harm would result from just
using a regular DPST Rocker?

Thanks,

Dave

Could it be a circuit breaker with external trigger to turn it off in fault conditions- I've seen
one of these before in a power supply.

 

[Dave]

Could it be a circuit breaker with external trigger to turn it off in
fault conditions- I've seen one of these before in a power supply.

Thanks for the suggestion. That's what it is: a thermal circuit breaker
with a rocker-switch built in. Searching on "rocker breaker," I found that
Schurter makes a nearly identical replacement, the TA45 series. I ordered
a TA45-326L150C0 from Mouser. Hopefully that will do the trick.