European treadmills on 208v

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Treadmills used in gyms (as opposed to home versions) are almost ALWAYS using 4 quadrant DC drives, meaning they are line regenerative to avoid having to deal with strong runners who can over-drive them. A 4Q DC drive is not going to give one tiny rat's butt whether it is 208, 220,221, 230, 240 etc., the motors are likely 180VDC and the drives are SCR based, so all that will happen in the drive is a rectification to DC.

But to this first point I raised; when I did some work for an OEM that made treadmills, they had issues with their "home" versions ending up in gyms because they were cheaper, then some strong runner would get on them and burn them out, because they were NOT line regenerative. If you over drive a treadmill motor that doesn't have line regen, it typically either trips on OV, 0r tries to "burn" off the energy in a braking resistor. Home models do that knowing that 99% of home treadmills end up as glorified clothes hangers and those that get used are used by people who can't over drive. But those resistors are not intended to be run continuously, they burn out. So I'm wondering if you have something like that going on here; the treadmills they bought from overseas were a "bargain" because they were not designed to be used in gyms. In my gym, I have noticed over the years that people tend to gravitate to "favorite" machines, maybe for proximity to TVs, other gym equipment with "eye candy", etc. It's possible that this only happens on some machines simply because some superman/woman athlete(s) decided that is the best place for them to run, but the machines cant's take their abuse.
 
Jraef said:
Treadmills used in gyms (as opposed to home versions) are almost ALWAYS using 4 quadrant DC drives, meaning they are line regenerative to avoid having to deal with strong runners who can over-drive them. A 4Q DC drive is not going to give one tiny rat's butt whether it is 208, 220,221, 230, 240 etc., the motors are likely 180VDC and the drives are SCR based, so all that will happen in the drive is a rectification to DC.
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It matters if you wan't to maintain a healthy commutation margin at all times. Assuming SCR control.
 
Besoeker said:
And then there is the frequency difference to consider.
Midlands UK - are you a Brummie?
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Indeed....but I was assuming that the motor is 'hiding' behind some kind of variable speed device, maybe a 4Q DC or AC so drive so not directly driven from the supply.

Not a Brummie....but close...ish..... I'm in Nottingham
 
AdrianWint said:
Indeed....but I was assuming that the motor is 'hiding' behind some kind of variable speed device, maybe a 4Q DC or AC so drive so not directly driven from the supply.

Not a Brummie....but close...ish..... I'm in Nottingham
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Could be variable speed in which case frequency is possibly less of an issue.

My younger daughter and two lovely grand girls live in Nottingham.....Sherwood area I think. We capture them now and again.
 
AdrianWint said:
A couple of 'concerns' if the equipment is designed for a UK supply:

1). Double pole switching/fusing : If the design is intended for use on our 230V Ph-N supply where the N is accepted to be maintained at ground potential, it may incorporate only single pole switching & fusing (in the 'hot' line only). This may not be compatible when operated at 208V (ie. hot-hot) in the US where double pole switching & fusing would be needed.
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Would that cause machine to fail, or is it more a safety issue?
 
readydave8 said:
Would that cause machine to fail, or is it more a safety issue?
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It's OK to only SWITCH one leg on a 208-240V load, because whatever it is will not operate without the other leg. But under our rules, you must have an OCPD on each ungrounded leg. So it would function, but it would be illegal (if that were the case that the unit was designed with protection on only one leg).
 
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