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samui99
08-17-2014, 10:34 AM
Hello

I wonder if anyone here has problems with black dust coming from their stairlift.

I have a Minivator (also known as Handicare and same as Age UK) straight stairlift which is about 4 years old now. Since we have had it we have had problems with silvery black graphite like dust coming off the track and getting onto the carpet. This dust makes a real mess and is quite difficult to clean off. I have been told by the engineer which services the stairlift that this is a problem with all stairlifts and difficult to avoid. However I have never heard of this before and can't find any mention of the problem online.

I wonder does anyone else have a similar problem with their stairlift and how do they keep it clean and stop it making a mess on their carpet.

Thanks
Samui

nukecad
08-17-2014, 02:14 PM
I'm a mechanical engineer and though I have never been involved with stairlifts the problem would seem to be an obvious one.

The dust is probably being caused by a bearing wearing away.

A lot of 'lightweight' bearings these days are made from graphite or tiny glass beads included in a nylon or other polymer matrix.
If the designer doesn't specify the right bearing they will wear away too quickly.
(We can all make mistakes but this sort of thing is usually because of cost cutting, the designer specifies one type of bearing but the purchasing dept. can get a similar one cheaper).

Another possibility with what I understand of stairlifts is that you may have some wheels running up the track, these would be made from the same materials but would have less of the graphite or glass beads in them.

Whichever is the case the fact that they are degrading and giving off the dust means that they are not suitable for the job.
I would contact the manufacturer of your stairlift, not the maintenance company, and point out your concerns, also ask if they can supply a metal bearing instead of the polymer ones.

nukecad
08-17-2014, 02:22 PM
I've just had another thought,

If your stairlift is on a straight run, i.e no curves, then it may be powered up and down along the track by a 'rubber' belt, if this belt is not tensionned correctly around the pulleys then it can start to wear away leading to the dust.

In this case I would expect it to make a squealing noise as well when the belt slips.

Fliss
08-17-2014, 06:46 PM
I have no idea why this is happening, I've had a stairlift for a few years and never had any black dust. So I don't think the manufacturers can say it always happens.

beau
08-17-2014, 08:04 PM
I too have never had black dust from my stairlift. Does seem like wear of some sort.

samui99
08-17-2014, 08:23 PM
Thank you for your replies. Knowing that others don't have this problem means it's not just a normal issue. I was skeptical when the engineer told me it was "compressed dust" and if this was normal everyone would be complaining about the mess on their carpets.

Nukecad, thanks for your answers, especially re the bearings. The more I look at the dust the more it does seem like some kind of carbon. It's very difficult to wash off and when it gets on the carpet if you brush it it tends to spread and makes things worse. It doesn't just wash away with water like normal dust, you need detergent to get rid of it. Anyway I shall call the manufacturer and see what they say and the servicing company.

nukecad
08-18-2014, 12:44 PM
Definately call the manufacturer, and ask if you can speak to someone in the design office about your problem.

From my experience at various workplaces if a customer with a problem gets to speak with one of the designers/draughtsmen we will take more steps to sort out the problem quickly and find out why it is happening in the first place.

If there is a customer service dept. they are usually only able to send replacement parts of the type you already have.
A designer can take it upon himself to source stronger or more suitable replacement parts, possibly in a different material, and usually issue them free of charge to solve the problem.

I have done just this in the past on various occasions once contacted directly by customers.

Often the design department are not informed of a potential problem until there have been a rash of complaints to the service centre, by which time there are a lot of unhappy customers.

beau
08-18-2014, 03:12 PM
Could it be that a carbon based lubricant has been used on the track and it is now drying out. If I remember rightly graphite is sometimes used.

samui99
08-18-2014, 05:30 PM
Thanks for further suggestions. For future reference to anyone considering a stairlift this is what I've discovered

After a number of calls today it seems like the problem is basically a design weakness with this model of stairlift - Minivator 950.

The manufacturer refused to let me speak to anyone technical or anyone in their service department as I didn't buy the Stairlift directly from them. They told me that they had only once heard from a similar sounding problem (really??)

I then called two other Stairlift dealers. One didn't have any ideas the other said they no longer supported this make of stairlift but the Minivator was known to get dirty because of the design of the mechanism.

I then went back to my local dealer and had a nice chat with the engineer which had previously serviced it. He explained the design problems and admitted that they didn't like dealing with Minivator stairlifts because of the problems with the compacted dust. The explanation he gave does now sound reasonable.

So long and short - if you are considering a Minivator stairlift be warned they are likely to ruin your carpet.

nukecad
08-18-2014, 08:32 PM
Did they explain where the dust was coming from?

I couldn't find any other complaints of this problem on the web.

Looking through the list of spares on various websites I see that the bushes and gears are indeed of the plastic type but the colours are white (nylon) or grey (probably pvc or abs) these would not give rise to any black dust.

What will give rise to black dust is something that I had overlooked, the motor brushes are carbon/graphite.
They are meant to wear away over time and this wear will give rise to a silvery/black very fine dust.
Usually any dust produced will be contained by the motor housing and can be cleaned out when replacing the brushes at a service.

However if the casing of the motor is not enclosed the dust will escape as seems to be happening to you.

I must warn not to cover any holes in the casing that the dust may be getting out of, these may well be needed to let air in or out for cooling and covering them could lead to overheating of the motor.

samui99
08-19-2014, 07:20 PM
Did they explain where the dust was coming from?

I couldn't find any other complaints of this problem on the web.

Looking through the list of spares on various websites I see that the bushes and gears are indeed of the plastic type but the colours are white (nylon) or grey (probably pvc or abs) these would not give rise to any black dust.

What will give rise to black dust is something that I had overlooked, the motor brushes are carbon/graphite.
They are meant to wear away over time and this wear will give rise to a silvery/black very fine dust.
Usually any dust produced will be contained by the motor housing and can be cleaned out when replacing the brushes at a service.

However if the casing of the motor is not enclosed the dust will escape as seems to be happening to you.

I must warn not to cover any holes in the casing that the dust may be getting out of, these may well be needed to let air in or out for cooling and covering them could lead to overheating of the motor.

Thank you for that. I will tell my father and perhaps he will be able to check the bushes or if not we will ask about getting them replaced.

nukecad
08-19-2014, 07:33 PM
Just a clarification here;

The things that I now believe are causing your dust are called brushes, not bushes.

Quick, hopefully not too technical explanation- bushes are solid bearings that support the rotating bits, brushes are replaceable parts of some electric motors that 'brush' against the rotating bit to transfer electricity to them.

Not all electric motors have brushes these are often called 'brushless motors' so they dont have these parts that wear away and give off dust. It seems from the spare parts list that the motor in your particular stairlift model does have brushes and so you are getting the dust.

samui99
08-19-2014, 07:40 PM
Yep sorry, don't know why I wrote bushes. I think brushes are quite often carbon aren't they.

nukecad
08-20-2014, 07:47 AM
Yes, brushes are usually made mainly of carbon/graphite.

In some motors they may be made of a phosphor bronze material, but these tend to be in heavy industrial motors that will be running 24/7.

Fitting new brushes may help or even stop your problem, but you will need the service engineer to do this for you.
Looking at the installation manual for your stairlift model the drive motor is not easy to get to.

samui99
08-20-2014, 08:39 AM
Yes, brushes are usually made mainly of carbon/graphite.

In some motors they may be made of a phosphor bronze material, but these tend to be in heavy industrial motors that will be running 24/7.

Fitting new brushes may help or even stop your problem, but you will need the service engineer to do this for you.
Looking at the installation manual for your stairlift model the drive motor is not easy to get to.

Thank you nukecad, you have been very helpful with this. BTW where did you find the installation manual? I looked for one online myself to try and see how the internal mechanisms all worked.

nukecad
08-20-2014, 05:28 PM
I had trouble finding it again too. (Found it easily this morning).

http://www.handicare.no/upload/Rehab%20Norge/Simplicity+%20Install%20Manual%20ENG.pdf

This is the manual for the installer showing how to cut and fit the track, fit the power unit, fit the seat, etc.,etc.
Has plenty of photographs of the various stages.

It doesn't really show the internal mechanisms as they are pre-built in the enclosed unit below the seat, you get the odd glimpse (fig 21) but no real good view. At least it gives you an idea of how it all goes together.

Hope its of use.
Steve