I installed a dc power supply as a replacement for a non working exciter. Could the polarity be reversed?
The DC power supply has no ARMATURE load-sensing compensation circuit. It is designed to hold a specific Voltage as its OWN load varies. ONLY.
The OEM Exciter DID have load sensing. It was tuned to work dynamically with the generator- all as a well-balanced "team", so to speak.
As load increased, Exciter and generator drew
greater field current through the primary generator so the Armature Voltage actually went UP to deal with the load. Your rig isn't delivering increased Field power. Holding it STEADY, rather.
That "dynamic" response was a MAJOR part of the exciter's job.
But it cannot do that job if it is no longer THERE and its replacement has a
different prime directive.
A Parker-SSD DC Drive has its OWN IR sensing feedback loop. Built-in.
Or can be switched to read from a tacho-generator, instead, for around 20 times the precision, given it also expands the covered RPM range. Check the comparison table in the manual.
Either way, it also boosts Armature Voltage to hold RPM under load. Doesn't need a Field involved to "JFDI". "Op Amps" and reference source sensing current flow, ELSE tacho-generator feedback as input, rather.
"RTFM".
Even if you do not have one of the drives.
It's a free download. And very educational. Same again Eurotherm-SSD's manual on their Field Regulator system in a separate box.
Load regulation was what the brilliant (in MANY things) Harry Ward-Leonard brought to the party. He was otherwise
not the first to ever build a Motor-Generator rig. Just the first to build an elegantly simple, stable, repeatable under load, and eminently controllable
VERY GOOD one. Serious DURABLE, too!
One of over 100 patents. If it matters. As it should do:
Harry Ward Leonard - Wikipedia
Simply put? Your rig has
none of the above.
Can't "get there from here" if it is indifferent AKA
blind to the inherently self-regulating feedback all others
put to good use.
TANSTAAFL .. all part of the "invisible" AKA "black magic" goodness of a(ny) OEM DC Drive 10EE, any era.
Absent that "stealth", built-in and taken-for-granted, feature, a drop in RPM under load is "just going to happen".
JFDWT.. or seek out a salvageable "rotating" exciter.. or even an SSD drive.
Depending on how much it actually matters to yah?
It might not be a big deal, given "ordinary" lathes often drop RPM a skosh under load, anyway? And still make PLENTY of useful chips.
Just not as "elegantly".....