Solenoids and a Question

[Madman]

So, in the past i thought solenoids operated on DC only. I have a Lionel "O" gauge operating car that operates on AC, as do all Lionel trains. The car in question has two miniature solenoids that push a plate that in turn unloads lumber from the car.

I have found miniature solenoids that will fit the application but are listed as DC. By the way, the solenoids presently in the car are pull type. An external spring returns the mechanism to resting position.

Here's a video of a similar, not mine, Moe & Joe operating lumber car.

 

[trammayo]

So, in the past i thought solenoids operated on DC only. I have a Lionel "O" gauge operating car that operates on AC, as do all Lionel trains. The car in question has two miniature solenoids that push a plate that in turn unloads lumber from the car.

I have found miniature solenoids that will fit the application but are listed as DC. By the way, the solenoids presently in the car are pull type. An external spring returns the mechanism to resting position.

Here's a video of a similar, not mine, Moe & Joe operating lumber car.

https://www.electronicspoint.com/threads/ot-how-does-and-ac-relay-solenoid-work.55602/

A bit like thje Winter Solstice - over my head too!

 

[PhilP]

Ah!
All to do with something called a 'shaded pole' within the solenoid..
It does work.. The theory is quite complicated (once you try to get into the maths)!

Lets just say it is to do with 'electrickery', and leave it at that..

BTW:
You can NOT do this with a DC solenoid in its' place, and an AC solenoid will not like DC up it!

 

[dunnyrail]

So, in the past i thought solenoids operated on DC only. I have a Lionel "O" gauge operating car that operates on AC, as do all Lionel trains. The car in question has two miniature solenoids that push a plate that in turn unloads lumber from the car.

I have found miniature solenoids that will fit the application but are listed as DC. By the way, the solenoids presently in the car are pull type. An external spring returns the mechanism to resting position.

Here's a video of a similar, not mine, Moe & Joe operating lumber car.

They are pretty quick but must have been so k.....d that they only manage a third of the load!

 

[trammayo]

Ah!
BTW:
You can NOT do this with a DC solenoid in its' place, and an AC solenoid will not like DC up it!

... Mr Mainwaring!

 

[Madman]

So what do I look for when searching for an AC powered solenoid ?

 

[dutchelm]

A coil has a greater AC impedance than a DC resistance. You may find applying AC to a DC coil will not pass enough current through the coil to operate the apparatus. It's a bit tial and error. Back in an earlier life we found many 110v DC relays would work on 240v AC.although they buzzed like hell.
The easiest way is to use a DC coil & a full wave rectifier.
(You have strange electric over there anyway)

 

[Madman]

A coil has a greater AC impedance than a DC resistance. You may find applying AC to a DC coil will not pass enough current through the coil to operate the apparatus. It's a bit tial and error. Back in an earlier life we found many 110v DC relays would work on 240v AC.although they buzzed like hell.
The easiest way is to use a DC coil & a full wave rectifier.
(You have strange electric over there anyway)

We have a few strange things over here that I will not elaborate on lest I get hollered at.....

 

[Deleted member 4232]

Moved

 

[Fred2179G]

Before you change anything, double check that it is AC. My understanding is that Lionel used DC to activate accessories. You pushed a button on the accessory controller and it injected a DC voltage on the track. AC devices ignored it.

 

[Madman]

I worked on finding why there was a short after the first one or two activations. Over on OGR forums, a member suggested trying to insulate the plunger from the frame. I did just that with some heat shrink tubing and it solved the problem.

In the photo below look at the plungers (silver pieces). What looks like a TEE is held in place by the forks (black). I simply covered the fork prongs with the heat shrink tubing.

 

[Huh? What?]

Before you change anything, double check that it is AC. My understanding is that Lionel used DC to activate accessories. You pushed a button on the accessory controller and it injected a DC voltage on the track. AC devices ignored it.

I don't think that would work. If you throw DC onto a line carrying AC, you don't get two separate electrical signals. You get and AC signal "riding" on a DC level.

For example: if you have a 120VAC ac signal, it starts at 0VAC, goes up to +120VAC then drops back to 0VAC, It then goes down to -120VAC and back up to 0VAC.

If you inject, say, a 20VDC signal onto the same line, all it does is shift the VAC signal upwards. The same 120V signal would start at +20VAC, go up to +140VAC, drop back to +20VAC, before dropping down to -100VAC and back up to +20 VAC.

The DC signal would, in effect, not exist.

 

[PhilP]

Yes it would..
Else how do you think 'phantom power' works on an audio line to power microphones and the like?

Though you do need to 'shield' your DC stuff, from the AC stuff, and vice-versa..

 

[Neil Robinson]

Before you change anything, double check that it is AC. My understanding is that Lionel used DC to activate accessories. You pushed a button on the accessory controller and it injected a DC voltage on the track. AC devices ignored it.

I seem to recall some years ago experimenting with an MTH PS2 fitted loco. I believe these had some compatibility with Lionel equipment. When running on AC a button could be pressed to activate the horn/whistle. If I remember correctly the button was a momentary normally closed switch in parallel with a diode. This was placed in one of the track feed wires and when pressed the track supply changed from AC to half wave rectified DC. Perhaps this would activate a DC relay with a suitable impedance such that it just buzzed with a low current uptake on AC. The MTH loco would slow down somewhat but with the log loader I guess the train is stationary anyway.