"Could you explain heat generation in hydraulic valve solenoid coils? If the temperature of the coil increases what will happen to the directional control valve's function?"The short answer to this is: the solenoid coil will fail and therefore the hydraulic valve itself will cease to function.In other words, the high inrush current generates more heat than can be continuously dissipated by the solenoid. So if the plunger is not able to be completely pulled into its coil - due to a mechanical problem with the valve for example, then the insulation around the coil windings will burn and the coil will short out.

But what could go wrong that would stop the solenoid plunger from being pulled in completely? Well, contamination is a common cause. When hard or soft particles invade the clearance between the spool and its bore, the solenoid may not have enough power to fully shift the valve's spool. This is often referred to as "silt-lock".If silt-lock is the problem, then replacing the solenoid is a waste of time. Replacing the entire valve will BUY some time - until it too becomes 'silt-locked'. The solution of course, is to get the contamination problem under control.

Bottom line: burnt-out valve solenoids is another cost of failing to properly control contamination. 

Fuel Shut Off Solenoid Fits CUMMINS 3930658 3932529 3935431 SA-4756-12 J93252 12volt

Part No.:3932529 3939700

Ref. No.:SA-4756-12 SA-4891-12

Excavator Hydraulic Pump Solenoid Valve For E320 E320B E320C 121-1491

Part No.:121-1491

Ref. No.: Red Dot KWE5K-31/G24D30