Re: CNC mill DC motor field wiring

Thanks for the replies. I will probably just leave the field at 200V
for right now. I was just concerned that perhaps I was running a
100V field at 200V and didn't want to burn out the windings. But
probably a 5HP motor would have a 200V field and I am doing things
correctly. I guess I could trace through the wiring on the broken 3
phase powered DC motor control to see what field voltage it supplied,
but I am ok with a top end speed of 1800 to 2000 rpm anyway.


Richard




--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Peter Seddon" <peter@s...>
wrote:

> The other thing to watch with low field conditons is flashover on

the

> brushgear - festive (much light and sound) but dangerous and

destructive. I

> would limit the field voltage variation to no more than half rated

value and

> some may feel that is overgenerous.
>
> Regards Peter
>
>
> ----- Original Message -----
> From: "Brian" <ka1bbg@w...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Saturday, December 14, 2002 12:50 AM
> Subject: Re: [CAD_CAM_EDM_DRO] CNC mill DC motor field wiring
>
>
> > Hi, watch out if you get the field too low in voltage the

armature can

> draw
> > huge quanities of current and do speed run-a-way. Its one way to

get more

> > rpm but one has to watch armature current carefully. Playing with

the

> field
> > voltage is a good way to get hurt and destroy equipment. be

careful! cul

> > brian f.
> > ----- Original Message -----
> > From: <skykotechnologies@y...>
> > To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> > Sent: Friday, December 13, 2002 11:24 AM
> > Subject: [CAD_CAM_EDM_DRO] CNC mill DC motor field wiring
> >
> >
> > > I finally got around to installing a 5HP 4 quadrant regenerative
> > > drive (from KB) on my shizuoka B3V mill. I didn't really know

the

> > > specs on the motor, except that it is a 5HP DC motor, so I

figured it

> > > was probably 180V armature, 200V field. The old broken spindle
> > > driver was labled 3.7KW DC motor speed control model 1-4064 by

Sanyo

> > > Denki Co.
> > >
> > > Anyway, it works just fine, except I don't know if it is

rotating as

> > > fast as it was designed. The field resistance is about 116

ohms, so

> > > I figured it had to be 200V. Would it hurt things to run it at
> > > 100V? I guess it is going to give reduced torque and double?

the

> > > speed, which might be too much for the bearings.
> > >
> > > Any idea what the designed max rpm on this mill is? The old

fanuc

> > > control panel had an analog spindle speed meter that has about
> > > 3500rpm and 740rpm as the max meter movement. That makes sense

as

> > > the mill has a geared head with a 5 or 6 to 1 ratio (haven't

actually

> > > bothered to measure the ratio yet). I would estimate the motor

is

> > > spinning much slower than 3500...perhaps 1800 or so.
> > >
> > > I just got a 240VAC 9.5 amp autotransformer at an auction, so I
> > > guess I could easily build a variable field voltage generator

with

> > > the addition of a small bridge rectifier....
> > >
> > > Thanks for any ideas or suggestions,
> > >
> > > Richard
> > >
> > >
> > >
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> you have trouble.
> > http://www.metalworking.com/news_servers.html
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> > http://groups.yahoo.com/group/jobshophomeshop I consider this

to be a

> sister site to the CCED group, as many of the same members are

there, for OT

> subjects, that are not allowed on the CCED list.
> >
> > NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY

POSTING THEM.

> DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
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