NJ Switch Machines - Failure Mode

Im not familiar with them. Many solenoids that do work will not take continuous voltage. Most switch machines,except Atlas have a limit switch or EOS switch (end of stroke) to shut off power when thrown. So they are only powered briefly. If that switch remains closed the solenoid will most likely burn up quickly.

Dale H

I think it would burn up it but not sure.   I have bunch of NJCB switch machines in service and have not burned one up yet.   I use momentary contact buttons to throw them.    It would take a while to do it in my opinion.   It would not happen in seconds, but maybe minutes.

I have had the cranks on the end of the throw rod break.   I save anyone that breaks and salvage parts.   I have been able to repair a few that way.

Here is a capacitor discharge circuit for Atlas,it should work with any solenoid.

LINK

Dale H

Atlas switch controller buttons are known to stick in the on position. This usually melts the switch machine.

I wired the coils through the DPDT lever switches on the side, so coils are disconnected after the throw.

Yes, they will fry.

I've fried a few coils on my NJs with a sticky DZ1000 controller.  First you hear a faint buzz sound, next comes the smell and the realization that a very reliable switch machine is about to be thrown out.

Thanks to all for your input.  My switch machine coil shows obvious signs of overheating: discoloration and melted insulation oozing from the coil. The switch machine is wired to disconnect power upon throwing.  Throwing is initiated either by a momentary switch controller or by the switch's automatic derailing prevention feature.  My guess is the switch machine hung up in mid throw leaving the coil energized when a train is parked over the switch.  Complete throwing of this particular switch has always been problematic.  Could be a Rix Rac/switch stiction problem.  I've solved other incomplete throw issues by wiring both sets of switch machine contacts in parallel to avoid disconnecting power too early in the throw cycle.  Dale H's capacitor discharge circuit I suspect would also do the trick. 

A DZ-1000 controller should not be used with the NJI switch motor.  It cannot handle the load.  That advice from Dennis Zander, owner of Z-stuff.  You've burned and welded the contacts.

Given the spark a NJI generates, I also would not use an AIU to throw the switch without wiring it through the side switches as described above.

I learned my lesson RJR.  I've got some old Lionel controllers that still perform great.

I use the old K-line lever switch controllers with LED bulbs.  Work great.

As RJR said you can't use the DZ-1000 to control the NJ switch machines for a number of reasons, one of which is low current rating.

By the way, has anyone ever noticed that the DZ-1000 controller LED sockets protrude beyond the back housing plane. If you mount these on a conductive surface you will short the circuit which fries the button switch.

I know if you try to throw a switch and if the iron core can't PULL IN, the coil will fry in seconds, this is true of any ac coil with an iron core . If it get's stuck and can't move your coil is destroyed very quickly!

Alan

Continuously powering either coil would definitely burn them up. It is a known problem with twin coil switch machines no matter who makes them.

Dale H's capacitor discharge circuit will solve the problem, those have also been in use with twin coil switch machines for many years. I bought an old used book on electronics for model rail roads from the late '60s or early '70s, it was mostly for HO, but it had one chapter devoted to capacitor discharge devices.  

In a thread some months ago on uncoupling tracks, I presented a circuit that would kill a circuit if it was conducting power for more than a few second, to go into the feed to all uncoupler controllers.  This might have a use in the feed to switch controllers if that feed powers nothing else.