L3130 Schematic question (stop solenoid)

[jmpratt]

When I look at the attached schematic, it appears that the holding coil (black circle) and relay coil (red circle) are always energized together because they have a common power source (blue circle). If that's the case, that would mean that anytime the key is on, the holding solenoid is energized, the relay is energized, and therefore the boost coil (other coil in the stop solenoid) is energized. That doesn't make any sense. Is the schematic wrong or am I missing something?



This link should have a better image:
https://drive.google.com/open?id=0B8Aca2gclLMhaE1jbzJrcTRSb3RETXV5OHVWTF92RnBRcDk4

 

[85Hokie]

image is too small to read - even after opening!

 

[jmpratt]

image is too small to read - even after opening!

I added a link to a large image. Here it is again.
https://drive.google.com/open?id=0B8Aca2gclLMhaE1jbzJrcTRSb3RETXV5OHVWTF92RnBRcDk4

 

[Technical Ted]

A lot of times circuits are wired so losing power kills the action. If relying on a solenoid to energize to "stop" or "kill" the device, if a wire or connection came loose you would not be able to shut down. So, relays are wired to be energized to enable things to operate and losing (or disconnecting) power to the solenoid shuts things down.

This is typical in industrial controls wiring anyways... For example, the master power control circuit relay (MCR) is energized when enabling the machine, but any emergency stop or other critical switch/sensor in the wiring string enabling the MCR can drop power and the MCR will de-energize shutting the machine down.

Is this what you are wondering about or am I missing the question?

Ted

 

[mendonsy]

I think the other thing that is confusing is that they call it a "stop" solenoid when it is actually a "run" solenoid. It must be energized for the engine to run and de-energized to stop the engine.

 

[jmpratt]

A lot of times circuits are wired so losing power kills the action. If relying on a solenoid to energize to "stop" or "kill" the device, if a wire or connection came loose you would not be able to shut down. So, relays are wired to be energized to enable things to operate and losing (or disconnecting) power to the solenoid shuts things down.

This is typical in industrial controls wiring anyways... For example, the master power control circuit relay (MCR) is energized when enabling the machine, but any emergency stop or other critical switch/sensor in the wiring string enabling the MCR can drop power and the MCR will de-energize shutting the machine down.

Is this what you are wondering about or am I missing the question?

Ted

Your missing my question a bit. Why are there two coils on the solenoid if they are both energized at the same time? One coil is 15 ohms, the other is .35 ohms (per the manual). If the high current coil is never turned off, why even have the low current coil?

-Jason

 

[100 td]

"Generally", solenoids have 2 circuits, a pull in and a hold in, pull in draws high current, hold in low current, are switched by 2 separate circuits, and may have a internal switch or resistor in the pull in coil. However, the internal circuit is not always shown, so a solenoid that has both coils energized may actually only have one circuit working after it has pulled in.
Also with redesign of solenoids, less stock inventory, ability to use 1 solenoid for various uses means a dual coil solenoid can be powered from a single source to work correctly, especially if it has an internal switch to isolate the pull in, or it's wound for permanent energization, not intermittent use.

 

[Technical Ted]

I don't have an answer for that. You would need more information. Maybe someone that has experience with this circuit might have an answer.

Ted

 

[sagor]

I suspect the "main" coil would draw too much current for the starter switch (run mode) to handle. Thus, one uses a smaller current relay that draws an amp or two (note it is on a 5A fuse, #10), to pull in with a contact in that relay that is rated for 30A, 40A or even 100A. That then allows the high current flow through the second solenoid/fuel valve, which is on the 30A fuse (#6) circuit.
It may also be part of some fail-safe system, but I don't see that in that schematic.

 

[OrangeColoredTractor]

When I look at the attached schematic, it appears that the holding coil (black circle) and relay coil (red circle) are always energized together because they have a common power source (blue circle). If that's the case, that would mean that anytime the key is on, the holding solenoid is energized, the relay is energized, and therefore the boost coil (other coil in the stop solenoid) is energized. That doesn't make any sense. Is the schematic wrong or am I missing something?

View attachment 29667

This link should have a better image:
https://drive.google.com/open?id=0B8Aca2gclLMhaE1jbzJrcTRSb3RETXV5OHVWTF92RnBRcDk4

Looks OK to me, remove power, engine stops. Default for a failure is engine stops. I am sure the coils consumes very little current, especially if its a 100% duty cycle with the engine running.

 

[OrangeColoredTractor]

I suspect the "main" coil would draw too much current for the starter switch (run mode) to handle. Thus, one uses a smaller current relay that draws an amp or two (note it is on a 5A fuse, #10), to pull in with a contact in that relay that is rated for 30A, 40A or even 100A. That then allows the high current flow through the second solenoid/fuel valve, which is on the 30A fuse (#6) circuit.
It may also be part of some fail-safe system, but I don't see that in that schematic.

Starter solenoids do have a pull in and a hold winding. The pull in winding is usually canceled out by a counter voltage. I am not seeing how this one is doing this though, ie both sides are grounded, the coil is the load, so anything after that is just a ground and no counter voltage???

 

[North Idaho Wolfman]

I do believe on that model that the solenoid has internal contacts in the stop solenoid that cut power to the pull in coil when the hold coil engages.

 

[jmpratt]

Thanks, everyone. If I get bored, I'll check the current in the solenoid to see if there is some kind of internal switch the disconnects the high current coil.

-Jason