Rework Station Pump - Can They Be Repaired ?

[stj]

Re: Rework Station Pump - Can They Be Repaired ?

smallest fuse you have a suppose - 250ma?

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

So do you also see 60~120V between the two wires of the pump?

Just saw this reply... yes I do, I see the same voltage at the pump as I do at MT2.

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

let's just do a quick test - connect the pump directly to the mains - through a small fuse please.

Can't find a fuse that small and of course this will be a one-way experiment should the coil begin to smoke and spark lol but I guess that would prove things one way or the other...

Except there are large power resistors on that board would they be to lower the current to the coils ?

Still can't understand how this device would oscillate at line frequency ! I would have thought the way to increase the pump output would be to increase the oscillation of the piston assuming the voltage provided was enough to power the magnetic fields.

[stj]

Re: Rework Station Pump - Can They Be Repaired ?

speed of pump movement is limited by the diaphrams pulling the pole to the center.
by using phase-control you vary the current in the coils.

i dont know what those resistors are for - ignore them

[juliadream]

Re: Rework Station Pump - Can They Be Repaired ?

Those resistors will serve the same function as they do in a dimmer.. as part of the capacitor charge/discharge diac trigger circuit (the variable one will be in series with the one to the top of the cap, and one of the others will be current limiting for when the triac fires, and also to make sure the cap fully discharges..

How these circuits work is the cap connected to the diac and the variable resistor network will slowly charge up, and at a certain voltage the diac will conduct switching on the triac and providing a discharge path for the cap.. once the voltage on the cap falls to below the diac forward voltage conduction point the circuit resets and the cycle starts over..

I think the problem is more likely (now we have sorted out the s/c triac) to be in the reed type valves in the mechanical side of the pump, or the diaphragms are not sealing properly.. maybe try greasing the pistons..??

how it works

http://www.homemade-circuits.com/201...c-flasher.html

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

The piston "floats" between the diaphragms there is no place to grease. The article talks about cap C1 used for inductive loads. Perhaps I should go over the components again when I get a chance.

[juliadream]

Re: Rework Station Pump - Can They Be Repaired ?

The piston "floats" between the diaphragms there is no place to grease. The article talks about cap C1 used for inductive loads. Perhaps I should go over the components again when I get a chance.

That would be a very good plan.. it's not a complicated circuit. Also try pushing the piston back and forward by hand (no power obviously) to make sure the pistons are actually doing what they should in their cylinders.. it should be like a horizontally opposed 2 stroke car engine.. piston one pushes out of the far end of the cylinder through a flappy type valve (or maybe some sort of slot in the cylinder wall.. can't think how.. too simple for sleve valves.. maybe just a bit of flattened rubber tube. or a tube with a pipe with holes in the sides.. some sort of one way valve....) while the other sucks air from the reservoir chamber in the middle past the piston..because the valve is closed due to the piston suction.. like a bicycle pump.... then the opposite happens.. once per left/right cycle..

That's how to think of it.. like two bicycle pumps back to back joined at the handle end.. with a tyre valve screwed in the end of each.. the pump bodies stay fixed and the handles move back and forth between them with the pistons where they usually are on the ends of the bits connected to the handles.....

now thinking out loud again.. if the rubber pistons don't reach to the cylinders and it all flaps about in open space in the middle.. possibly the holes in the pistons have stretched and they have worked their way too far down the shaft.. there is a nut I see at the end of each shaft.. maybe the pistons should be immediately behind that rather than half way down as the photo shows.. that's my best guess so far..

(no sleep and painkillers today.. bit hazy.. hope that makes some sort of sense)

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

Nah physically everything looks pretty good and I was able to drive the piston in both directions with five 9-volt batteries. I still believe I have a circuit malfunction which was not cured by replacing the failed triac.

[juliadream]

Re: Rework Station Pump - Can They Be Repaired ?

well that's my lot.. mine has a rotary motor driving a pair of cams on a shaft against fixed diaphragms.. fixed speed.. neat little pump tho.. would be interested to see a trace of the control, circuit

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

Update - never resolved this and ended up replacing the station with a different model.