Transformer question

[Trond]

The transformer for my IFF Ampliator enlarger has two switches on it. The first one is obviously the power switch, but the second one doesn't make anything obvious happen. It can be on or off and everything behaves the same.

The switch is wired up to something inside, but I don't know much about electronics to make any sense out of it.

Does anyone have an idea?

Trond

 

[domaz]

Can't tell from that picture. Is that a relay to the left of the transformer? I hope your not powering your enlarger on with the case open- that transformer would probably blow you out of your chair.

 

[Ian Grant]

De Vere transformers have two switches, it's usually to do with linking to some types of Timer.

Ian

 

[Ian C]

On some DeVere power distribution boxes, such as the one for the 5108, there are two switches. The first is marked “Mains: On/Off” for power on or off.

The second is marked “Stabilised/Unstabilised.” Selecting “Unstabilised” sends unstabilzed line current directly to the Dichromat head.

Choosing “Stabilised” sends the power through a voltage stabilizer, if one is connected to the appropriate connector on the power supply, and then to the Dichromat head. This keeps the bulb voltage constant for consistent print-to-print color work.

The 5108 doesn’t use a transformer on the US and Canada version since it uses 4 300-watt 120-volt ELH bulbs that match the input line voltage.

 

[Trond]

Can't tell from that picture. Is that a relay to the left of the transformer? I hope your not powering your enlarger on with the case open- that transformer would probably blow you out of your chair.

There is a relay to the left of the transformer. The transformer is connected directly to a wall socket, and it has another plug that goes to the timer. I think the relay is used to switch the lamps on and off. It has some large components at the back which looks like resistors.

I suppose it doesn't matter what the switch is for when it doesn't do anything!

Trond

 

[RH Designs]

Is there a connection for a timer? If so, the second switch may bypass it for a "focus" function.

 

[ic-racer]

Base on the picture this is what I think:

The transformer converts 220v to 48v at 700watts maximum for the bulb
The resistors drop that lower for some other thing on the enlarger. Like an indicator light or the fan.

Are there wires to the lower switch? Where do the wires come from? Maybe it is to turn on or off the alternate supply , like to turn off any indicator lights.

 

[MPandolfo]

The resistors drop that lower for some other thing on the enlarger.

Those resistors are more likely part of a snubber circuit.
Note the capacitors associated with them.
Possibly, that circuit is there to protect the lamp or the relay contacts.

 

[Trond]

Those resistors are more likely part of a snubber circuit.
Note the capacitors associated with them.
Possibly, that circuit is there to protect the lamp or the relay contacts.

This sounds plausible. The power supply makes a clicking sound when the lamps turn on and off, and I suppose that comes from the relay. The filter scale lamps didn't work when I got the enlarger, and in the end I connected a small external power supply to the head just for the filter scale lamps. Perhaps the the second switch is there just to turn on and off the these lamps as ic-racer suggests. I will open it up again and check where all the wires go.