Ramp up down switch single phase motor

[bigspark17]

Weired one. Looking for info or past experiences. Called to a garage very old ramp 40+ yrs old not working. Very old switcc looks like its burnt out, so before i take on finding a replacement i wanted to make sure motor ok. So bypassed up down switch and turned on isolator. (Single phase motor) and the ramp started mooving up, great i thought, so then reversed the polarity hoping the ramp would then go down, but to my dismay the ramp went up again.!
How can i get the motor to reverse?

 

[westward10]

When you say you reversed polarity how did you do this.

 

[bigspark17]

When you say you reversed polarity how did you do this.

When bypassing the up down switch straight from iso i switch L & N to motor

 

[James]

I think you may be out of your depth on this one.
there are many ways that it may reverse the travel of the ramp but swapping L and N on a Single phase ac motor is never going to be the answer.

 

[westward10]

As above you in general terms you need to flip the start winding only but it may be more involved than that.

 

[snowhead]

Ramps usually lower by gravity, but have to go up first so the safety locks can be released.

Having touched it, before you leave to need to make sure you've tested all functions and all the safety devices.
That's assuming your insurance covers you for working on them.

(Disclaimer, there's more than 1 way used to lift ramps, cables, chains, hydraulic, possibly more)

 

[bigspark17]

I think you may be out of your depth on this one.
there are many ways that it may reverse the travel of the ramp but swapping L and N on a Single phase ac motor is never going to be the answer.

I agree i am on this one.
So can you eloborate on the many ways it may be reversed? However it can be done used to be done via this old switch? (If i can attach pic?)

 

[James]

Can you post a pic of each side of the lid?
it’s early and I am still on my first coffee but I can’t see any reverse method, looks like an old DOL starter from first look.

 

[bigspark17]

Can you post a pic of each side of the lid?
it’s early and I am still on my first coffee but I can’t see any reverse method, looks like an old DOL starter from first look.

No pic of cover. It was just an up and a down switch though. Thats why i was baffled. Like you said i was out of my depth but seems you dont have much more of a clue than me…

 

[mainline]

Weired one. Looking for info or past experiences. Called to a garage very old ramp 40+ yrs old not working. Very old switcc looks like its burnt out, so before i take on finding a replacement i wanted to make sure motor ok. So bypassed up down switch and turned on isolator. (Single phase motor) and the ramp started mooving up, great i thought, so then reversed the polarity hoping the ramp would then go down, but to my dismay the ramp went up again.!
How can i get the motor to reverse?

How is the ramp being driven ? Is it a ram pushing cable ? Or is it direct to some gearbox type setup ?

Has it got a capacitor ?

 

[James]

No pic of cover. It was just an up and a down switch though. Thats why i was baffled. Like you said i was out of my depth but seems you dont have much more of a clue than me…

The poiNt is, the location of the buttons, correspond to what they push on the rear plate, I.e. one at the top pushes a N/o contact next to the coil.

 

[mainline]

How is the ramp being driven ? is it a ram pushing cable ?

You need to reverse the winding polarity

 

[bigspark17]

The poiNt is, the location of the buttons, correspond to what they push on the rear plate, I.e. one at the top pushes a N/o contact next to the coil.

Picture attached where the two contacts pushed down on. Hope this is helpful to you and you are able to share your wisdom now?
Are you able to explain how this switch can change the direction of the motor alone?

 

[bigspark17]

You need to reverse the winding polarity

This control box was the only device between the isolator and the motor. Nothing else. How can this box do that??

 

[Lucien Nunes]

Is this a hydraulic ramp e.g. an old Bradbury? If so the motor does not reverse, the ramp lowers by gravity when a valve is opened. This unit is just a single-direction starter. There is a mechanical interlock between the hydraulic valve and the starter.

A forward / reverse starter for a split-phase, capacitor-start or cap-start/cap-run motor has separate contacts for the start and run winding in each direction. They are cross connected so that both contactors energise one winding with the same polarity in both directions, but the other winding with opposite polarity for one direction. It doesn't actually matter which of the start and run windings is reversed, the key is that one is reversed relative to the other. This means that a reversible single-phase motor* must have four live cores in the cable to the starter as the start and run windings are connected separately. A single-direction motor has the two windings connected together internally and therefore only needs two live cores.

*Excluding small permanent split capacitor motors that have a common terminal in the winding, hence only three outgoing connections.

What makes you think the starter is burnt out?

 

[James]

Thanks @Lucien Nunes
i could see a contact was missing and as said I post number 8 it looks like a direct on line motor starter and overload unit.
I was wondering if it might be a hydraulic unit and if so, the motor only runs to lift, it will descend by gravity when valve is open.

 

[bigspark17]

Is this a hydraulic ramp e.g. an old Bradbury? If so the motor does not reverse, the ramp lowers by gravity when a valve is opened. This unit is just a single-direction starter. There is a mechanical interlock between the hydraulic valve and the starter.

A forward / reverse starter for a split-phase, capacitor-start or cap-start/cap-run motor has separate contacts for the start and run winding in each direction. They are cross connected so that both contactors energise one winding with the same polarity in both directions, but the other winding with opposite polarity for one direction. It doesn't actually matter which of the start and run windings is reversed, the key is that one is reversed relative to the other. This means that a reversible single-phase motor* must have four live cores in the cable to the starter as the start and run windings are connected separately. A single-direction motor has the two windings connected together internally and therefore only needs two live cores.

*Excluding small permanent split capacitor motors that have a common terminal in the winding, hence only three outgoing connections.

What makes you think the starter is burnt out?

Thanks lucien nice to hear a full and informative reply. The mechanics said there was smoke coming from the switch and the little transformer looks worse for wear, what would this transformer do?
Yes its a very old hydrolic ramp with no safety locks its really old,
Btw no valve to drop down

 

[mainline]

Thanks lucien nice to hear a full and informative reply. The mechanics said there was smoke coming from the switch and the little transformer looks worse for wear, what would this transformer do?
Yes its a very old hydrolic ramp with no safety locks its really old,
Btw no valve to drop down

I have never seen and can't think of a reason for a hydraulic ramp to need a motor that reverses.

Is this a 4 poster ramp ?

How is the ramp driven, is the ram pushing cables ?

 

[SparkySy]

I have seen a very old 4 post in the past that had a motor set up like yours with the motor only running in one direction. There was a lever on the hydraulics connected to a valve that changed the flow direction. It was lethal as there were no interlocks on it either so in the event of hydraulic failure if you were under it you would have been a red pancake!
I politely declined to look at it as I didn't fancy that on my conscience.
Sy

 

[James]

Thanks lucien nice to hear a full and informative reply. The mechanics said there was smoke coming from the switch and the little transformer looks worse for wear, what would this transformer do?
Yes its a very old hydrolic ramp with no safety locks its really old,
Btw no valve to drop down

The “transformer” is a solenoid that pulls the motor contacts closed.
if it is overheating, it is either faulty or the mechanical parts are not moving correctly.