Components for AC-DC rectifier

C

ChrisJLove

New Member
Hello. I am looking for some advice on components for a voltage rectifier circuit which controls a solenoid. Moisture caused tracking across the circuit board and blew some or all of the components. The part is obsolete but I'm sure the individual components can be replaced as the PCB is in good condition. I am trying to identify the type of bridge rectifier and the orange and blue components as shown in the picture. Any advice would be much appreciated.
 

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The bridge rectifier can be tested with a multimeter. If you find something the right size, voltage and current rating, it will be fine. You are likely to find a wide choice of devices. It is also quite likely that the bridge rectifier is massively over-rated, so it could well be rated at many times the voltage and current that it is used at.

The orange device is a 33 nF, 400 V capacitor. You may find that a replacement will be marked 333 instead of 33K.

The blue device is likely to be a capacitor to reduce noise. The circuit will most likely work without it.

Can you photograph more of the board to give some context?
 
Sure. This is the original board. There are two identical circuits on there one for the pilot and one for main solenoid, which are both rated at 220-240v
 

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Two bridges on one board is a bit strange.

My guess is that the blue part is an MOV - Metal Oxide Varistor, a transient suppressor. The 250 V marking is common. Anything the same size (and rated for 250 Vac) will work.

Does this board run directly off the mains, or is it downstream or a power transformer?

ak
 
Thanks for your replies, I have since discovered that the coil on one of the solenoids is open circuit, and no replacement available, so back to square one.
 
ChrisJLove said:
Thanks for your replies, I have since discovered that the coil on one of the solenoids is open circuit, and no replacement available, so back to square one.
Click to expand...

Can you not rewind the solenoid?, they are usually just a simple winding on a core.
 
Not super critical but does control what drive level is needed.

So just get some enabled wire, preferably same gauge, and rewind. First unwind
bad winding, to get its length, then use that same length for new winding.


Regards, Dana.
 
I have attempted to measure the old winding and there is a huge amount length wise, I gave up around the 500 m mark and there is still the vast majority remaining.
 
ChrisJLove said:
I have attempted to measure the old winding and there is a huge amount length wise, I gave up around the 500 m mark and there is still the vast majority remaining.
Click to expand...

If it's a 240V solenoid, then there's going to be a LOT of thin wire.

But if you can't get a replacement any more, then the only option really is to rewind it.
 
Even thought the unit is obsolete it is possible that the solenoid valves are available from the manufacturer from the solenoid valve manufacturer.
If you plan on rewinding as you say that there are two solenoid valves I suggest measuring the resistance of the good one so that you can check that you have put enough turns on the one you are rewinding. I suggest initialy putting on more wire than seemed to be on it before. Then measure the resistance. If it is higher than required then remove some wire until it has about the right resistance.
Another posibility is to calculate the required wire gauge to rewind to work on a lower voltage (Say 24 volts.) then use a small transformer to power it.

Les.
 
Measure winding R. For that gauge you have a ohms/foot resistance.
So calculate the length from that.

Even easier if you have ohm spec of relay just use that with measured
gauge to figure the length.



 
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