Cold stair lift motor

I'm looking at adding a resistor or bulb inside an Acorn stair lift motor housing to keep the temperature about 40degF. The unit is in an unheated area and temps get too low for the motor to turn normally. I considered an electric blanket or pad but having an elderly person messing with something on the stairs is not a good idea. Also, there's the issue of having a separate part and cord to deal with.

Cheat this out and see what you think. I have done this when setting up electronic devices in remote locations, installed in an insulated box with a car battery & resistor. In this case a night light bulb might be another choice.

Sketch

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Reply to
Snuffy "Hub Cap" McKinney
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[Light bulbs burn out]

I don't understand -- doesn't the motor travel as well? So, how does it receive power? (or, are the 2x12V the EXISTING power source for the motor?)

Likewise, are the contacts already present (to provide charging current to the traveling battery pack)?

I.e., is the only addition you are making that of the "heating load"? And, you presumably want it on at all times (possible exception being while the chair is travelling -- as the motor is generating its own heat *and* this would just be an added load on the batteries!)

[Is there a switch that tells the motor to turn on? As such, can you tie into that to cause the heater to turn OFF when motor is ON?]

Is the motor frame (reasonably) accessible? E.g., could you wrap some heating tape around it KNOWING that operating the tape at

24V -- instead of 120V -- will cut the heat output to something more desirable (I have no idea what the nominal output "per foot" of those tapes is likely to be)
Reply to
Don Y

Is the motor under the stair? How is the power supplied to the motor? Makes me wonder if you can use the existing wiring some how.

Are you able to contact the manufacturer? Maybe they have a low ambient temperature kit. Why reinvent the heater wheel?

Reply to
Stormin Mormon

Good point

Motor is part of the chair. Batteries power the motor. When chair is at full top or bottom, battery contacts mate with rail contacts to keep fully charged. Transformer pluggs into the only receptacle which is at the bottom and connects with both top and bottom rail contacts.

Yes

Correct. I want to keep the compartment around the motor above 40 deg F when the night temperature drops to 20-30 deg. If it goes below 20, no one will be using the chair.

On all the time.

There is a switch. Good point. I'll look into that. If the chair got stuck mid-way for some reason, the resistor could possibly let the batteries run down.

Thanks. That might be better than a resistor -- will check it out.

Reply to
Snuffy "Hub Cap" McKinney

Good point

Motor is part of the chair. Batteries power the motor. When chair is at full top or bottom, battery contacts mate with rail contacts to keep fully charged. Transformer pluggs into the only receptacle which is at the bottom and connects with both top and bottom rail contacts.

Yes

Correct. I want to keep the compartment around the motor above 40 deg F when the night temperature drops to 20-30 deg. If it goes below 20, no one will be using the chair.

On all the time.

There is a switch. Good point. I'll look into that. If the chair got stuck mid-way for some reason, the resistor could possibly let the batteries run down.

Thanks. That might be better than a resistor -- will check it out.

Simliar to this one:

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This shows replacing the batteries. You can see the gears when he opens the side panel.

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Reply to
Snuffy "Hub Cap" McKinney

Have you tried Customer Service?

Dave M.

Reply to
David L. Martel

Exactly. And, you (or "they") are likely not to consider that this is happening. If you use a *light* as a load, then they MIGHT notice the light still being on -- but, what are they going to DO about it?

One could argue that the chair now risks "getting cold" and being hard to start. But, this is an exceptional condition -- one where you expect to have to "do something more" to get things back to normal...

Note that even without modifying/augmenting the switch (to turn the heater off when traveling), you could possibly mount a magnetic reed switch in series with the load and a magnet affixed to the stairs (top and bottom "parked" positions). So, when the chair is in those *positions*, the circuit closes and provides heat.

You can also design something to sense power being APPLIED (from the contacts) and engage a relay coil letting the relay contacts engage the heater load. E.g.,

C O + >--+---|>|-----> to relay coil N | T | A +---|>|-----> to motor circuit C T - >--------------> to relay coil and motor circuit S

The |>| being diodes. The top one is a dinky diode as it only needs to pass enough current to engage the relay coil. The bottom one only has to pass enough current to charge the battery! (unless the battery is DEAD at the end of the stairs and the "charger" is effectively trying to power the motor THROUGH that diode -- in each case, the charger's current capability determines the size of the diode)

Relay contact only need to carry the load for the heater (7W / 24V ~= 1/4 A). In practice, you'd size larger to help resist contact fusing (DC being unfortunate)

A higher tech solution would be to run a light "idle current" through the windings -- use the *windings* as the heating element -- but you'd need to be able to better characterize the motor in order to exploit that (i.e., if this was a desirable feature, that's how a manufacturer would approach it).

Reply to
Don Y

C O + >--+---|>|-----> to relay coil N | T | A +---|>|-----> to motor circuit C T - >--------------> to relay coil and motor circuit S

I should have explained this, just in case... :<

The role of the diodes is to prevent power from the batteries ON THE "MOTOR CIRCUIT" from energizing the relay when there is NO power on the "contacts". The second diode blocks the current from flowing right to left (battery being connected on the right side of it) and into the relay coil -- which would turn the relay on all the time (as long as the batteries had power!). We only want the relay to turn on when power is available at "contacts".

[The first diode *could* be omitted but there are some cases where it can be of use]
Reply to
Don Y

Sheesh! Get nauseous watching the world spin through his viewfinder! That;s the problem with "amateur" videos... they concentrate on MAKING them instead of VIEWING them!

Given how close together things are (batteries and circuit board abutting drive motor), you might want to consider how hot your heater will get and where that heat is likely to radiate.

Of course, I suspect the motor gets warm during use so imagine the batteries and circuit board EXPECT that, nearby.

Unfortunately, no shots of the backside of the switch so hard to tell what sort of connections it has available. I imagine three positions: ON OFF ON (UP, STOP, DOWN)

And, I'm sure any "technical literature" (service manual) doesn't reveal much in the way of detail. (doesn't even tell you how large the "charger" is!)

Reply to
Don Y

Its highly possible the batteries are going bad.

cold temeratures lessen battery power

Reply to
bob haller

If the motor is DC motor driven by a battery, I'd use battery blanket(warmer)

Reply to
Tony Hwang

housing to keep the temperature about 40degF. The unit is in an unheated area and temps get too low for the motor to turn normally. I considered an electric blanket or pad but having an elderly person messing with somethin g on the stairs is not a good idea. Also, there's the issue of having a se parate part and cord to deal with.

electronic devices in remote locations, installed in an insulated box with a car battery & resistor. In this case a night light bulb might be another choice.

Is this in a lower area available to the disabled who enter the structure? Isn't the upper elevation warmer? Can't it be stored at a warmer lever and "called" to the lower level?

Reply to
bob_villain

"contacts".

Thanks for taking the time with this. I enjoy this sort of thing myself. Relays and PLC's are a lot of fun. Will have to do some testing with different size resistors and go with your relay method. Can't plan for every situation, but not draining the battery is important.

Thanks again, my friend!

Reply to
Snuffy "Hub Cap" McKinney

Not since they moved off shore. A few years ago they were extremely helpful but now all they do is refer to website or read some rote nonsense.

Reply to
Snuffy "Hub Cap" McKinney

Batteries here are new. This happens every winter.

Reply to
Snuffy "Hub Cap" McKinney

motor housing to keep the temperature about 40degF. The unit is in an unheated area and temps get too low for the motor to turn normally. I considered an electric blanket or pad but having an elderly person messing with something on the stairs is not a good idea. Also, there's the issue of having a separate part and cord to deal with.

up electronic devices in remote locations, installed in an insulated box with a car battery & resistor. In this case a night light bulb might be another choice.

Is this in a lower area available to the disabled who enter the structure? Isn't the upper elevation warmer? Can't it be stored at a warmer lever and "called" to the lower level?

Stairway is in an enclosed space with little insulation from the outside air. Temp at top probably warmer, but still not much warmer than outside air. Only switch for this model is on the arm of the chair.

Reply to
Snuffy "Hub Cap" McKinney

Try it without the relay, first. I suspect you (or someone) can sort of keep an eye on it to make sure it is "parked" properly while you get a feel for how well this is working.

Granted, the heater will sap a bit of capacity from the battery while traveling but hopefully not enough to cause the chair to stall (those batteries are pretty substantial and I'm sure the chair is geared way down! Probably lose more in the gear train than actually moving the person!)

Reply to
Don Y

you should ask in sci.electronics.repair and maybe sci.electronics.misc

Reply to
Micky

snipped-for-privacy@googlegroups.com...

or housing to keep the temperature about 40degF. The unit is in an unheate d area and temps get too low for the motor to turn normally. I considered an electric blanket or pad but having an elderly person messing with someth ing on the stairs is not a good idea. Also, there's the issue of having a separate part and cord to deal with.

p electronic devices in remote locations, installed in an insulated box wit h a car battery & resistor. In this case a night light bulb might be anoth er choice.

? Isn't the upper elevation warmer? Can't it be stored at a warmer lever an d "called" to the lower level?

air. Temp at top probably warmer, but still not much warmer than outside ai r. Only switch for this model is on the arm of the chair.

add insulation.

Reply to
bob haller

motor housing to keep the temperature about 40degF. The unit is in an unheated area and temps get too low for the motor to turn normally. I considered an electric blanket or pad but having an elderly person messing with something on the stairs is not a good idea. Also, there's the issue of having a separate part and cord to deal with.

up electronic devices in remote locations, installed in an insulated box with a car battery & resistor. In this case a night light bulb might be another choice.

Thanks, I did post at the repair group and got a few good replies there. Not like here though. This group is the best starting point for just about anything including computer issues. There are dozen or so regulars who have done just about everything around the house, always helping the beginner folks.

Reply to
Snuffy "Hub Cap" McKinney

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