An electric pto has 2 different common failure modes: windings and pulley bearing. Other than common, mechanical damage is possible, but seldom.
Windings failure: As current passes through windings, the wire gets hot and expands. When finished using the pto, wires cool down and contract. The movement scrapes the thin varnish type insulation from the wires and the wires short out against one another. The strength of an electro magnet is determined by the number of coils and the amperage in the wires. With the wires shorting out, there are fewer coils and the magnet has less strength. When the wires short, this also reduces the total resistance of windings and allows more current to flow through often resulting in overloading you electrical system and/or blowing a fuse. Typically, you'll want about 4 ohms resistance in your windings. You can often have that when the windings are "cold"/not expanded, but it may change/get reduced when the windings warm/expand and short.
Pulley bearing failure: I believe this is your situation. When pto is engaged, the pulley is rotating at the same rpm as the crankshaft and the bearing inside the pulley is just there to take up space. When pto is turned "Off", the pulley should stop rotating, but with the crankshaft still rotating in /with the bearing. There're springs in the clutch disc that pull the disc back against the metal housing and act a a "brake". When pto is turned "On", the magnetic force of the windings overcome the springs and the clutch engages. When turned "Off" the disc springs back against the housing and prevents the blades (or whatever is attached to pto) from free wheeling.
I'm thinking either a bearing failure or possibly some of the loose debris you found inside got into the bearing and locked it up. I'm not familiar with the exact makeup of your clutch, but you should have bearing inside of the pulley. Replacing this bearing could give you a spare pto clutch!
Hopefully, you've got a better feel of what's going on inside your clutch! Bob
Windings failure: As current passes through windings, the wire gets hot and expands. When finished using the pto, wires cool down and contract. The movement scrapes the thin varnish type insulation from the wires and the wires short out against one another. The strength of an electro magnet is determined by the number of coils and the amperage in the wires. With the wires shorting out, there are fewer coils and the magnet has less strength. When the wires short, this also reduces the total resistance of windings and allows more current to flow through often resulting in overloading you electrical system and/or blowing a fuse. Typically, you'll want about 4 ohms resistance in your windings. You can often have that when the windings are "cold"/not expanded, but it may change/get reduced when the windings warm/expand and short.
Pulley bearing failure: I believe this is your situation. When pto is engaged, the pulley is rotating at the same rpm as the crankshaft and the bearing inside the pulley is just there to take up space. When pto is turned "Off", the pulley should stop rotating, but with the crankshaft still rotating in /with the bearing. There're springs in the clutch disc that pull the disc back against the metal housing and act a a "brake". When pto is turned "On", the magnetic force of the windings overcome the springs and the clutch engages. When turned "Off" the disc springs back against the housing and prevents the blades (or whatever is attached to pto) from free wheeling.
I'm thinking either a bearing failure or possibly some of the loose debris you found inside got into the bearing and locked it up. I'm not familiar with the exact makeup of your clutch, but you should have bearing inside of the pulley. Replacing this bearing could give you a spare pto clutch!
Hopefully, you've got a better feel of what's going on inside your clutch! Bob
