hi there friends
firstly i am a civil engineer by profession and i'm female - so i honestly don't know anything about electronics. but i have a huge problem. i bought this artromot K1 continuous passive motion machine 11 months for $4350. after sleeping with it for 11 months, i have become extremely electrically sensitive to it. now, once it's turned on, i can't even stand a couple of meters away from the machine for a few minutes without becoming extremely nauseated, disorientated, my brain feels numb, i have loud ringing in my ears and i feel very sick and these symptoms last for hours or days. after these symptoms started, i realized that the artromot K1 wasn't earthed. so i earthed it. but it didn't fix the problem. then i thought it was maybe the magnetic fields or the RF coming off the machine, so i mitigated those issues but still, i couldn't be near the machine without becoming terribly unwell. then i contacted a guy in the USA who deals with this kind of stuff and he told me that the problem is the harmonics being produced by the switch mode power supply - which i can hear these harmonics by turning on a AM radio to no station and putting it near the machine.
i don't want to sell this machine because i need it for a hip problem i have (long story). and i'd lose too much money on it by trying to sell it. so i was wondering if any of you guys might know if it's possible to make this machine just run from a DC battery so that i can ditch the AC circuit board entirely? as i understand it. there's a variable speed DC motor - there's a hand piece that goes with it and that can vary the speed and the angle that the machine goes at. i would be really happy if the machine just went at one speed and one set of angles so that i could ditch the hand piece entirely and run the motor at a single DC speed. by doing this, do you think it would be possible to get rid of all the AC stuff that's making me so sick? i got this idea from a youtube video i watched where this guy converted his microscope from running on AC to DC. this is the video i'm talking about:

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one person that i consulted told me that it wouldn't be possible but i just can't see how it couldn't be possible if i'm happy to stick to one motor speed and one set of angles. so that i just turn the machine on .... start it ... it runs at one speed, then i turn it off. with no other electronic needs. i need to be able to run the machine about 5 hours per night, 5 days per week for years to come. the thing is that i don't think just making the AC circuit board sit farther away from me will fix my sensitivity to it. i need to get rid of all the harmonics associated with the SMPS all together. below i've attached some photos of what the machine electronics looks like and i took a photo of what it says on the side of the machine. i also attached the user manual which has electronic details in it. i think it steps the voltage down from 240 V to 24 V and the current rating is 850 mA to 370 mA. i would be SO SO SO grateful for some of your opinions. then i can take what you say and find somebody in australia (where i live) and tell them that you guys said it's possible and this is how thank you so much for any replies in advance. leesa

 

Using a linear power supply instead of a switched mode one may solve your problem. Two 12 volt sealed lead acid batteries could supply enough power but it would depend on weather the main electronics board required exactly 24 volts. This is because when fully charged they would give about 27.6 volts and drop to about 23 volts when nearly discharged. If you problem only occures when the motor is running it could be the way that the speed controller works that is causing your problem. (In which case a linear power supply or batteries would not solve the problem.) Do you have the problem near other reasonably modern electronic equipment ? The reason for asking this question is that most modern power supplies are switched mode. Even if other switch mode power supplies do not cause you a problem it could be that just the switching frequency used in this one causes you a problem. (They dont all use the same switching frequency. I don't think the microscope video is relevant as it looked like the power supply in that was a normal linear supply. The video did not give much information. Thanks for giving a clear description of your problem. You will probably get some more replies. There are many clever people on this forum.

Les.

 

Using a linear power supply instead of a switched mode one may solve your problem. Two 12 volt sealed lead acid batteries could supply enough power but it would depend on weather the main electronics board required exactly 24 volts. This is because when fully charged they would give about 27.6 volts and drop to about 23 volts when nearly discharged. If you problem only occures when the motor is running it could be the way that the speed controller works that is causing your problem. (In which case a linear power supply or batteries would not solve the problem.) Do you have the problem near other reasonably modern electronic equipment ? The reason for asking this question is that most modern power supplies are switched mode. Even if other switch mode power supplies do not cause you a problem it could be that just the switching frequency used in this one causes you a problem. (They dont all use the same switching frequency. I don't think the microscope video is relevant as it looked like the power supply in that was a normal linear supply. The video did not give much information. Thanks for giving a clear description of your problem. You will probably get some more replies. There are many clever people on this forum.

Les.

hi les. thank you so much for taking the time to read my post and reply. i'm very grateful. i feel sick even when i just turn the machine on, when it's not moving up and down. then i get even sicker when the machine starts moving. i've noticed that the noises from the AM radio are different when the machine is turned on but not moving and when it's moving. i know when i visit my stepfather in his man cave (shed), i quickly get sick in his shed as well - he's got all sorts of stuff like welders etc in the shed (but i've never gotten sick from visiting his shed before i became electrically sensitive to this machine). but around my house with other household items i don't notice it as pronounced (like when i'm using my juicer or blender). i made a video this morning of what the CPM machine sounds like when it's going (through the AM radio). i was so sick after making this video. i notice the sound is even in the power cord as well. i know people who become electrically sensitive like me refer to these harmonics coming from things like SMPS as "dirty electricity", i'm not sure if it's the electronics board or the DC motor which requires 24 volts? i've got a feeling it's the DC motor which requires 24 volts. if the speed is variable for the DC motor, does that mean that the voltage requirement would change with a change in speed of the motor? these are things about electronics which i don't understand. here is the link to the video showing this AM radio noise interference from the CPM machine when running.

 

Your picture 1 of 4 is the switch mode power supply and the red and black wires will be the 24 volts DC output. (I did a search on the web to see if I could find a schematic for your machine but I found no technical information. You would need to get someone to check that the power supply is 24 volts DC output before trying it with an alternative power source. The output from the power supply looks like it goes directly to the electronics board which will control the motor speed. It is possible that the motor need some of the electronics board just to work. (I could not see from the pictures how many wires connect to the motor. If there are only two wires to the motor then it could probably work without the electronics board. The juicer and blender will not have switched mode power supplies as the motors will be powered directly from the mains. Things like televisions, DVD player and computers will have switch mode power supplies. You would probably pick up electrical noise from most switch mode power supplies using an AM radio.

Les.

 

Does the motor itself have a label on it stating its power supply requirements?
As Les hinted, the motor speed control almost certainly uses high speed pulsing (Pulse Width Modulation). A motor of any substantial power driving mechanical stuff having high inertia or friction will likely suffer unless it is given a 'soft start'; so avoiding use of a speed control may not be possible.

 

Hi Alec,
I was actualy thinking the motor may be a brushless DC motor and the electronics for it may be on the PCB. I was wondering if it was a PM DC motor if the motor could be driven straight from a battery of a voltage that gives the speed that is required. There was a comment that variable speed was not required.

Les.

 

Hi Alec,
I was actualy thinking the motor may be a brushless DC motor and the electronics for it may be on the PCB. I was wondering if it was a PM DC motor if the motor could be driven straight from a battery of a voltage that gives the speed that is required. There was a comment that variable speed was not required.

Les.

hi les and alec. thanks so much for explaining that to me and thank you for taking the time to help me. ... i've taken some photos of the motor and the wires into the motor. the only writing i can see on the motor is at the end of that copper thing ... see below. also, oh no les - does this mean really bad news? ........hopefully i've captured the fact that there are many wires going into the motor. all of the colours that come from the electronic board seem to go into the motor. would i have to get another motor which only uses the red and black wire or is there a way to change the electronics board so that i can use this motor without the electronics board?

thank you so much for your time

 

Does the motor itself have a label on it stating its power supply requirements?
As Les hinted, the motor speed control almost certainly uses high speed pulsing (Pulse Width Modulation). A motor of any substantial power driving mechanical stuff having high inertia or friction will likely suffer unless it is given a 'soft start'; so avoiding use of a speed control may not be possible.

hey les .... doesn't that speed control/electronics board work on DC too because the red and black wire go to the the electronics board? does that mean that there is variable DC running through those red and black wires depending on what speed i want the machine to go at? i was just wondering about this. is this why the battery which would just be allowing one voltage through wouldn't work if we just hook those red and black wires up to a DC battery?

is there any other way to get rid of all those harmonics coming off that SMPS that's running through the power cord (is that stuff actually also being emitted through the metal frame by conductance?)

thanks so much
leesa

 

hey les .... doesn't that speed control/electronics board work on DC too because the red and black wire go to the the electronics board? does that mean that there is variable DC running through those red and black wires depending on what speed i want the machine to go at? i was just wondering about this. is this why the battery which would just be allowing one voltage through wouldn't work if we just hook those red and black wires up to a DC battery?

is there any other way to get rid of all those harmonics coming off that SMPS that's running through the power cord (is that stuff actually also being emitted through the metal frame by conductance?)

thanks so much
leesa

Red and black i would expect to be fixed DC voltage. 24v was mentioned earlier; not sure where that came from. It needs to be checked. Do you have a multimeter?

 

Red and black i would expect to be fixed DC voltage. 24v was mentioned earlier; not sure where that came from. It needs to be checked. Do you have a multimeter?

hi strantor .... thanks so much for your comment. yes i have a multimeter. i don't know how to use it without potentially electrocuting myself but i have one i was told by a guy who works on these machines (he's overseas at the moment) that the rectifier (?) drops the voltage down from 240 volts to 24 volts. but when i look in section 8 specifications in the user manual it says this:
Input ratings: 100 – 240 Vac / 50 – 60 Hz
tolerance -15 % to +10 %
Current consumption:100 V 240 V
standby (ON):5 VA 5 VA
operation (maximum):40 VA 40 VA
this user manual is in full above but i print screened this bit attached. is that DC voltage they're talking about? does that mean that's variable voltage to the electronics board and motor from the circuit board?
thanks so much in advance.

 

i found this old service manual online (attached below). the circuit board with the transformer on it looks very different to my machine and the model in the service manual is earthed (mine is not - the company said they didn't earth it because it's double insulated - whatever that means - mine spews out heaps of voltage in my opinion but anyways ..... ). so i've also attached this schematic from this old service manual which mentions 24 V power supply ... i don't know how relevant it is given that it's an older model but i thought i'd mention that i found this. do you guys make sense of this in combination with the voltages mentioned in this machine's service manual? sorry and thank you so much ...

 

oops - i just realized that VA doesn't stand for voltage. omg .... sorry.

 

Yes i saw the manual page about the voltage. It refers to mains (AC) voltage. The wide range of acceptable input is typical of switching power supplies.
It's reasonable to assume this guy knows what he is talking about I guess. But I would still set the multimeter to DC volts and check the output of the red and black wires.
shouldn't take long; insert the probes before powering it on, then power it briefly to confirm 24VDC.
If it's 24VDC then I would try replacing the switching power supply for an old school regulated transformer type DC supply like this:
http://www.ebay.com.au/itm/DC-Power...406588b&pid=100005&rk=1&rkt=6&sd=142336241997

If you look for a better deal, look for something like shown with the big transformer inside and big smoothing caps. 1.6A or higher.
if you find something smaller, it's probably another switching supply.


Do laptop chargers cause you problems?

 

hi strantor:

thank you so much for your input. the regulated transformer type DC supply.... does this power supply mean that the motor will be powered directly from the mains like les said my juicer and blender are above? do you know if it would be producing harmonics? - apparently it's the harmonics in these SMPS which can make folks sick if they're around them too long like i was (sleeping with it for so long). i will check the laptop battery - thank you for the suggestion. i have one but i haven't turned it on for ages. if it makes me sick, does that mean that this regulated transformer type DC supply won't work? currently i'm on a desktop computer sitting about 1.5 meters away from it.

 

hi strantor:

thank you so much for your input. the regulated transformer type DC supply.... does this power supply mean that the motor will be powered directly from the mains like les said my juicer and blender are above?

No the motor will still be powered via the control board. But I strongly suspect that won't be an issue. I am convinced that it's the power supply causing you problems, not the motor control board.

do you know if it would be producing harmonics? -

yes but the frequency will be 50 or 60Hz, whatever the mains frequency is in your area. This is the low pitch hum you hear when you walk past a large transformer.
I have never heard of these frequencies causing grief. Higher (tens or hundreds of thousands of Hz) frequencies are the problem

apparently it's the harmonics in these SMPS which can make folks sick if they're around them too long like i was (sleeping with it for so long).

i will check the laptop battery - thank you for the suggestion. i have one but i haven't turned it on for ages. if it makes me sick, does that mean that this regulated transformer type DC supply won't work? currently i'm on a desktop computer sitting about 1.5 meters away from it.

Not the laptop battery, the laptop charger. Reason I ask is that you can find a 24V/2A laptop charger for a fraction of the cost of what I linked.
Laptop charger is still a SMPS (switch mode power supply) but I've never heard of them causing problems. Every SMPS operates at a different frequency, some seem problematic, others not. Unless you live in an isolated cabin, you are surrounded by SMPS all the time. The PC you're using right now has a rather large SMPS in it, and you haven't indicated it to be an issue. If the laptop charger works just as well, you can remove the power supply board from your device and use the laptop supply instead, with the SMPS box a couple of meters from you, by the wall outlet.

 

No the motor will still be powered via the control board. But I strongly suspect that won't be an issue. I am convinced that it's the power supply causing you problems, not the motor control board.


yes but the frequency will be 50 or 60Hz, whatever the mains frequency is in your area. This is the low pitch hum you hear when you walk past a large transformer.
I have never heard of these frequencies causing grief. Higher (tens or hundreds of thousands of Hz) frequencies are the problem




Not the laptop battery, the laptop charger. Reason I ask is that you can find a 24V/2A laptop charger for a fraction of the cost of what I linked.
Laptop charger is still a SMPS (switch mode power supply) but I've never heard of them causing problems. Every SMPS operates at a different frequency, some seem problematic, others not. Unless you live in an isolated cabin, you are surrounded by SMPS all the time. The PC you're using right now has a rather large SMPS in it, and you haven't indicated it to be an issue. If the laptop charger works just as well, you can remove the power supply board from your device and use the laptop supply instead, with the SMPS box a couple of meters from you, by the wall outlet.

hi strantor: thank you so much for taking the time to explain all that. honestly i was thinking about it and i do believe that i am being affected by this computer. this morning i turned the CPM machine on for like 3 minutes and i was deadly sick afterwards. then things improved a little. then when i was typing and looking before at the computer, i got off, and now i feel like i want to vomit ... my brain feels like it is stinging. i feel it's been difficult to tell what's making me worse when i feel so sick after the initial exposure to the CPM - especially lately when i've been turning it on every day to test it and look at it. if you know what i mean ... like am i not feeling better for day because of a small exposure to the CPM or are these feelings being propagated by continual exposure to SMPS in other items now. i've never had issues with any of these devices before the CPM issue. but i do know people who can't go near a computer or even a wired telephone now due to the same kind of issue i am having. here is an example of some of them but it's very depressing to watch (not that i expect you to watch it, but just as a reference):

is there a way to not have a transformer in the CPM machine at all? do you personally think that it's possible to eliminate the transformer - the AC to DC conversion all together by using an external DC battery for example? i don't know if it's practical as i need to use it 5 hours per night, 5 days per week for the unforeseeable future for years to come.

thanks so much for your time in advance.

 

Sure a couple of car batteries in series should hold up for 5 hours at a time.
Charge them outside when not in use.

 

Sure a couple of car batteries in series should hold up for 5 hours at a time.
Charge them outside when not in use.

oh thank god, that's really encouraging. thanks for giving me your opinion on that. i appreciate you taking the time to read and help