99Yam help needed

[boscoe99]

how were you reading 20 amps between all 3 phases? The 20 AC amps were from the single phase PMA.
I am having a hard time envisioning the hook up.
there are 3 wires coming out of the PMA & those go into the RR
Maybe you just clamped onto each of those 3 individual wires and they each read 0 amps? I put the clamp on meter around each wire. One at a time. To get the AC current readings.
Or maybe you were measuring between phases some how?
did you measure any ground current somewhere? The ground lead from the R/R was measured using the clamp on meter. To get the DC current.
unless the system is referenced to ground somewhere, I do not see how excess would be able to be shunted off to ground.

Now a Y configuration with the center point grounded would work

on the single phase set up
I would guess that most all of that 20 AC amps were being shunted to ground, and very little was being used to create that 1 amp of DC.
as the DC load was added, less AC was shunted off to ground and more of it was used to create the DC called for.

All I know is what I can see on the meter. Not understanding much of it.

[boscoe99]

Now here is a diagram from Yamaha that shows the configuration for a three phase PMA. In which case the regulator is connected to the DC output.

A wye winding with the center point not being used.

[boscoe99]

Photos to follow this PM.

[99yam40]

OK so it is a Y set up and not a delta.
I guess those are zener diodes that bleed off excess voltage,
but I have no idea what the rectangle is that they are tied into.

[boscoe99]

I believe the zener diodes are within the rectangle. That send current to the gates of the SCR's so they can close to shunt AC current to ground.

The Yamaha bigger lighting coils use a Y configuration. The 3 phase PMA that I have uses a delta configuration.

I lament not having an old Yamaha block with its flywheel and lighting coil installed so I could see what is to be seen with it. Oh well.

[99yam40]

Do SCRs allow current flow in both directions when the gate is closed?
still trying to figure out how the shunted voltage/current get back to the coils in the circuits

[boscoe99]

You are asking questions well out of my pay grade.

My belief is that with no voltage to the gate there is no current flow through the SCR. Once the gate has a voltage applied to it (via the Zener diode I believe) the SCR allows voltage to be shunted from the coil to ground. Thus keeping the voltage down

https://www.electronics-tutorials.ws...thyristor.html

[boscoe99]

This seems to be a pretty good theory of operation for a shunt type of rectifier/regulator. Although it does not go into details as to how the switching from the AC to ground gets done. No mention of zener diodes or SCR's.

https://www.electrosport.com/pages/t...g-system-works

[boscoe99]

This is what I am seeing PMA current on. Hall effect sensors. Agrees with a clamp on meter.

[99yam40]

I got my hands on a GE ECM electric motor out of my brothers HVAC air handler.
it is one of those variable speed 120/240V motors.
he kept it from his old unit when he got a new system installed.

I tried to find a way to run it without all the boards because he did not keep those.
only thing I found online was a way to test the motor my putting 240v for power and 24vAC control power on 8 of the 16-pin control c connector, but that did not make it turn.

So I decided to open it up to see what was inside.
there are 3 magnets glued to the rotor,
and lots of coils around the case(stater maybe).
there are 3 wires coming out of the back end that hook to another part stacked onto the motor.
on line they say it has 3 phase windings.
I hooked a meter to 2 of the wires and turned the motor by hand and got 4 - 5 v ac.
Need to come up with a way to spin it up and see what kind of voltage and current I can get out of it.
I will try to post a pic
GE ECM 2.3 motor 2.jpg