AC motors + VFD are usually a great choice, and mostly 220-240V in the
EU/UK, or 440V (same-same).
Imho.
Older treadmill motors used to be DC PM magnet.
I have 10.
180DC 6000 rpm, 2.5 Hp theoretical max.
Nonsense re 2.5 hp.
I also have now a real 2.5 kW ac (servo) motor on my lathe, 2.5 kW
continuous duty output 24x7, aka industrial use.
It is about the same size, maybe 10% bigger than the silly open-frame
treadmill motors.
The old 1.5 kW lathe 220v induction motor was much bigger.
20% bigger section size ?? fora 1.5 kW +/- vs the ac new motor at 2.5 kW.
My Ac servo drive might be similar to what Chris M. refers to.
In any case, such motors will last 10.000+ usage hours in 24x7 use or
whatever, near coolant sprayed all the time in machining.
Imho .. Treadmill motors are fine for very occasional use, esp. lower loads..
The bigger/better commercial treadmill motors are probably fine for any
extended use - as such per power ..
I think none, zero, will last near salt water past 1-3-5 years.
I simply think corrosion will kill them.
Based on 2k machine, 6k+ motors, I looked at.
--
As far as commercial offerings ..
Some people on this list may offer DC motors / controllers from a
commercial marine-type supply.
I have zero personal interest commercially.
But the fact is that the sellers here have excellent results in
technical and commercial terms.
*Some* special DC motor/controller combos are good for marine use.
Some of the ones posting here sell such kit.
They have an excellent rep - and I would expect the products to be
equally good.
There is a lot of evidence that the best marine retrofit kits are great
- as sold by the commercial vendors here.
Extremely good stuff technically has been made since 1940s in sometimes
unusual formats.
The modern DC *marine* motors and controllers seem to be fine.
--
Recap imho - 4 cases:
Cheapest:
1.
Basic DC + controller / treadmill.
Weak on the small ones, good on the commercial/indistrial ones, I think
they will corrode.
2.
Good:
3-phase motor, and VFD.
Use a GFI. Faster if possible std is 15 mha iirc.
Cheap motor, excellent efficiency, endless cheap replacements of motor
and controller.
*Must* use double insulated cable, re: VFD- motor which is a trivial cost.
*Use* proper marine glue+shrink sleeves on connectors, tinned cables,
VFD-motor, typically 2 m length.
Using 200-400V AC is not dangerous at all, as such.
It is *not* dangerous, and a basic gfi will trip, but any high voltage
3-phase installation will usually trigger an investigation re: any
issues/accident etc.
3.
Commercial kits.
Mostly Dc with high amp motors.
Very good from EV boat suppliers.
The directives actually limit DC stuff to 80V- 48V is really pretty safe.
Typical welding and plasma cut is 40-48V.
4.
AC drives etc.
Best technically, not so usual, needs skills or integration.
On 14/01/2018 17:09, Chris Morriss chris.morriss@ouroboros.myzen.co.uk
[electricboats] wrote:
> AFAIK, looking at the controller they use, these are AC drive,
> brushless permanent-magnet motors, rather than old-fashioned AC motors
> used with variable frequency drives.
--
-hanermo (cnc designs)
Posted by: Hannu Venermo <gcode.fi@gmail.com>
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