4 post Bradbury liftmaster dol starter

[Welshgixxer]

The operating controls on mine are two push buttons and a lever. The ramp, when in use doesn't rely on the hydraulic ram to keep it in position - there is a metal bar alongside the ram housing which has rectangular holes in it about every two inches, you raise the ramp slightly higher than you need, then lower it slightly, and a solenoid operated peg pushes into the hole in the bar that is along side it, taking the entire weight of the ramp bed and whatever is on it.
The LH push button on the control panel starts the motor/pump, retracts the peg, and raises the ramp. You then release the button, pull the lever downwards, and the ramp lowers slightly onto the peg.
To lower the ramp, you push the fist button momentarily to raise the ramp slightly and take the load off of the peg. Next, you push the RH button, which powers the solenoid that retracts the peg. This button is held in, and the lever pulled down, which opens the oil return valve, allowing the ramp to descend. To stop the ramp part way down, you release the RH button, peg goes in, then you release the lever, when the peg reaches the bottom of its 2" hole.
Does yours work the same way?

Bri

I remember reading how it works (year, maybe years ago) and will have notes somewhere - from memory, simpler than yours - lever up for up, mechanical lock to hold, lever down returns fluid to tank, lowering lift.
Trying to take it one step at a time - getting it to move 1st.
It came in parts - trying not to be too optimistic seeing as the rotary switch internals were literally in bits.

 

[brianmoooore]

When I bought mine, it had been under three feet of floodwater a couple of weeks earlier!

 

[timhoward]

Mechanical external 'up' mechanism appears to close contact (top right, beneath wheel) - but no continuity across A-L1, B-L2, C-L3 when closed

I have manually closed the coil contact and have continuity across A-L1, B-L2,C-L3.

I haven't been able to understand from photos how the lever moves the contact, but is there any adjustment facility? It sounds as though it is supposed to fully close the contact.

 

[Welshgixxer]

I haven't been able to understand from photos how the lever moves the contact, but is there any adjustment facility? It sounds as though it is supposed to fully close the contact.

Sorry Tim, I should have provided an explanation to accompany photos. Moving the [post mounted] lever operates (through mechanical linkage) a mechanical spring loaded 'pivot' attached to the Dol starter front cover - which depresses the button (eg green - if lever up) on the Dol starter enclosure. Both buttons have rods attached to their rear - green is the shorter. The green button rod depresses the spring loaded contact plate below the adjustment wheel and completes circuit. I will take a close look to see if I can adjust rod length - if that's what you mean. - I could also wire it up and carefully depress contact manually with cover off - make sense if knew wiring ok first?

 

[brianmoooore]

Looks like you're going to have the problem of either finding a 230V coil for that contactor, or arranging a modern contactor so that it can be operate by the existing mechanical linkage.
Could possibly be solved by a panel mounted pushbutton, as on mine, and two handed operation.

 

[timhoward]

It would be a doddle to start again with a new 230v starter and an auxiliary safety button for the UP operation as Brian said.
The main question in my mind now is how "Down" works....I had imagined the DOWN lever was also operating a mechanical oil return, but now the principle of the lever and the rods has been explained I'm shifting to believing it's an electrically operated return valve?
Maybe annotating the photo of the inside of the DOL would help, showing exactly what UP and DOWN are pressing inside.
I'm thinking that as well as interrupting the coil, DOWN must close two contacts somewhere too.

 

[brianmoooore]

If the OP's ramp uses a solenoid operated latch to lock the ramp in position, like mine, and is single lever operated, then there must be contacts to power that solenoid when the lever is pushed down.
It's unlikely that the oil release valve is electrically operated, because that would make it either fully closed or fully open, and wouldn't allow the descent speed of the ramp to be controlled.

 

[Welshgixxer]

When I bought mine, it had been under three feet of floodwater a couple of weeks earlier!

Brian, Lucien, Tim

I'm not very good at leaving things I don't completely understand so before I move on to resolve the practical issue of incorporating a 230v dols would someone please confirm the correctness of my wiring diagram.

I am attaching an image of the Dols and my basic wiring diagram interpretation of it. I have coloured in live & neutral to distinguish them from hardwiring.

2 things (I am aware of) I don't understand:
1, why 2 of the wires exiting the coil join at a terminal?; and
2, assuming I can use 'L3-C as I have to provide current to the off switch (NC) when on switch (no) released, any idea how I would facilitate the 'orangey '(on diagram) connection to C?

Ps. The purple highlighted circle on the wiring diagram indicates the rocker that opens the off switch (NC) operated by the red button.

Of course I could have it all wrong!

Won't let me add images- to follow hopefully

Thanks again.

Si

 

[Welshgixxer]

Brian, Lucien, Tim

I'm not very good at leaving things I don't completely understand so before I move on to resolve the practical issue of incorporating a 230v dols would someone please confirm the correctness of my wiring diagram.

I am attaching an image of the Dols and my basic wiring diagram interpretation of it. I have coloured in live & neutral to distinguish them from hardwiring.

2 things (I am aware of) I don't understand:
1, why 2 of the wires exiting the coil join at a terminal?; and
2, assuming I can use 'L3-C as I have to provide current to the off switch (NC) when on switch (no) released, any idea how I would facilitate the 'orangey '(on diagram) connection to C?

Ps. The purple highlighted circle on the wiring diagram indicates the rocker that opens the off switch (NC) operated by the red button.

Of course I could have it all wrong!

Won't let me add images- to follow hopefully

Thanks again.

Si

 

[Welshgixxer]

Please ignore yellow cable - forgot to remove it.
Oil release to reservoir is mechanical, allowing oil return to reservoir.