Re: Bench testing solenoids...the right way...advice please

Posted by HH56 On 2023/2/22 10:14:33

The solenoids need a large amount of current when pulling in. Your rectifier setup may not be able to supply that much current to a surge load. Once it pulls in the heavy pull in coil is disconnected and the hold coil keeps the plunger extended requiring only a few amps to stay in this condition. Better would be to use a battery as the power source and make sure the connecting wires are at least as large as those in the car.

The R-11 solenoid has two terminals. The pull in and hold coils are connected together inside the case and terminal 4 supplies power to both coils. Terminal 6 is for the ign cutout circuit. To activate the R-11 you need a connection to the case for ground and another to 4. Again, power supply and wiring must be capable of supplying a heavy surge of current for at least a second or so.

The R-9 solenoid is a bit different in that it has 4 terminals with the pull in and hold coils being separately powered. Terminal 3 is the hold coil and 4 is the pull in coil. Terminal 6 is for the cut out circuit and 7 is for controlling the dash indicator light. To activate that solenoid both terminals 3 and 4 need to be connected together and then both powered at the same time via a heavy wire and solid power source, case still being ground. In actual use, the hold coil, terminal 3, is in series with one of the relay coils so operates at a slightly different voltage. When testing try not to leave it connected to direct power longer than necessary or it could overheat.

On both solenoids, once the plunger is almost all the way out an internal contact opens and cuts power to the pull in coil. At that time the hold coils will keep the plunger extended. The hold coils are not strong enough by themselves to make the plunger move against the heavy springs. On the R-9, if both 3 and 4 are not powered simultaneously, the solenoid will "machine gun". The solenoid will pull in, internal contact breaks the connection to the pull in coil and the plunger relaxes only to start the action over again as soon as the internal contact closes because there is no hold coil to keep the plunger extended.

The internal contacts for the pull in coils were a service item and do arc, spark and wear. If they are not making good contact so the pull in coil can get activated the solenoid will never pull in.