Cold stair lift motor

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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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http://oi67.tinypic.com/t9jmac.jpg
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On 2/18/2016 9:45 AM, Snuffy "Hub Cap" McKinney wrote:

[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)
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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.
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in message

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: http://www.acornstairlifts.com/stairlifts/straight-stair-lifts
This shows replacing the batteries. You can see the gears when he opens the side panel.
https://www.youtube.com/watch?v
ŽDq3qpPbZ0
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On 2/18/2016 2:44 PM, Snuffy "Hub Cap" McKinney wrote:

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!)
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On 2/18/2016 2:36 PM, Snuffy "Hub Cap" McKinney wrote:

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).
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On 2/18/2016 4:49 PM, Don Y wrote:

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]
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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!
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On 2/18/2016 8:19 PM, Snuffy "Hub Cap" McKinney wrote:

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!)
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On 2/18/2016 11:45 AM, Snuffy "Hub Cap" McKinney wrote:

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?
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Have you tried Customer Service?
Dave M.
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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.
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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.
Not since they moved off-shore? Orlando Fl is where they claim to be. So it's been years since you've tried customer service? Why do you think that customer service, which you haven't called is still bad? It's an 888 number.
Dave M.
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On Friday, February 19, 2016 at 1:24:03 PM UTC-5, David L. Martel wrote:

Orlando FL is where the corporate offices are.

So what?
Corporate Offices in the US and an 888 number doesn't mean that the Customer Service department hasn't been outsourced and moved offshore.
Is the concept of US based companies using offshore call centers new to you?
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Derby,
Who cares where the call center is? Does Snuff want an answer or not? Here he is, looking for answers from people who will not examine his device and know very little about it Acorn may have a simple answer but more likely they will have a local service man. Perhaps this guy will even be a US citizen.
Sheesh, Dave M
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On Saturday, February 20, 2016 at 7:02:51 PM UTC-5, David L. Martel wrote:

You were the one who brought up the location and the fact that there's an 888 number.
All I did was point out that the location of the corporate office and the fact that it's a US based phone number doesn't tell us anything about where their Customer Service Is located.
Let's recap..
You: "Have you called Customer Service?" Snuffy: "Not since they moved off-shore." You: "Not since moved off-shore? Orlando, FL is where they claim to be."
I don't care where the call center is. All I was doing was pointing out that your response about Orlando and an 888 number doesn't mean anything as far as its actual location.
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Derby,

No, the OP brought up the belief that the company has moved "offshore", whatever that means. Maybe it's Hawaii.

Actual location of what? The guy's got an elevator chair that doesn't work. He has hypothesized that the cause is the cold. He needs someone to make a service call, diagnose, and fix the chair. He will not get that here. He needs to call Customer Service, regardless of where it is. They will hook him up with a local repair guy. I know this is a DYI site but the suggestions are uniformly whacko. Before he "fixes" the thing he needs to diagnose the problem
Dave M.
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On Saturday, February 20, 2016 at 9:52:34 PM UTC-5, David L. Martel wrote:

It obvious that you have no clue what I am trying to say and it's not worth trying to explain it again.
Moving on...
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Oh you boys. LOL!
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Well, I took your advice and called it and by golly I got a real Floridian! And the feller knew his stuff. He said the indoor version used the same motor & grease as the outdoor version which would stand up to 20 deg F or lower - which is the number I gave him.
Saved me a bunch of work. Next time I'm over at that house I will look at it again and see exactly where it could be binding.
Thanks again Dave - first step, read the manual....
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