Ramp up down switch single phase motor

bigspark17 · Apr 7, 2022

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 · Apr 7, 2022

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

bigspark17 · Apr 7, 2022

westward10 said:
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 · Apr 7, 2022

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 · Apr 7, 2022

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

snowhead · Apr 7, 2022

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 · Apr 8, 2022

James said:
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?)

[ElectriciansForums.net] Ramp up down switch single phase motor

James · Apr 8, 2022

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 · Apr 8, 2022

James said:
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 · Apr 8, 2022

bigspark17 said:
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 · Apr 8, 2022

bigspark17 said:
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 · Apr 8, 2022

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

You need to reverse the winding polarity

bigspark17 · Apr 8, 2022

James said:
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 · Apr 8, 2022

mainline said:
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 · Apr 8, 2022

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?

Ramp up down switch single phase motor

bigspark17

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westward10

bigspark17

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James

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westward10

snowhead

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bigspark17

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James

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bigspark17

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mainline

James

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mainline

bigspark17

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bigspark17

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Lucien Nunes

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