[NSRCA-discussion] Himax 6330 rebuild

[Patrick Harris]

Which results in more heat? Correct.


On Thu, May 2, 2013 at 12:55 PM, Bob Kane <getterflash at yahoo.com> wrote:

> This knowledge is in the dusty mental archives from my university days,
> but basic motor theory will show a motor develops a voltage when it spins.
> We will call this the "back EMF" voltage.  It is easy to measure with a
> brushed DC motor, hook it up to a voltmeter and spin it. You will see the
> voltage rise as the RPM increases (and drop as it decreases). This voltage
> is a function of many things, but we will focus on RPM and the strength of
> the magnetic field. The current drawn by a motor is the difference between
> the supplied voltage and the "back EMF" voltage developed by the motor.
>  Since the back EMF voltage is a function of how fast it spins, it will
> draw little current when unloaded, and the as we load the motor with a prop
> the current will go up.
>
> Weak magnets will cause the motor's back EMF voltage to go down and result
> in an increase of the current drawn by the motor.
>
> Bob Kane
> getterflash at yahoo.com
>   ------------------------------
>  *From:* Patrick Harris <harris7148 at gmail.com>
> *To:* General pattern discussion <nsrca-discussion at lists.nsrca.org>
> *Sent:* Thursday, May 2, 2013 3:31 PM
> *Subject:* Re: [NSRCA-discussion] Himax 6330 rebuild
>
> Verne,
>
> I was thinking that may be the issue. I pulled it already so no way to do
> an amp draw.
>
>
> On Thu, May 2, 2013 at 11:29 AM, Verne Koester <verne at twmi.rr.com> wrote:
>
> If the motor is demagnetized (usually caused by overload and/or
> overheating) the amp draw will increase dramatically. Of course to know
> that, you have to have a baseline amp draw from when the motor was new to
> compare it to. What you’re describing sounds like your old motor was
> demagnetized. You could try comparing the amp draw on your old motor with
> the amp draw on your new one.****
> ** **
> Hope this helps.****
> ** **
> Verne Koester****
> ** **
> *From:* nsrca-discussion-bounces at lists.nsrca.org [mailto:
> nsrca-discussion-bounces at lists.nsrca.org] *On Behalf Of *Patrick Harris
> *Sent:* Thursday, May 02, 2013 1:57 PM
> *To:* jpavlick at idseng.com; General pattern discussion
> *Subject:* Re: [NSRCA-discussion] Himax 6330 rebuild****
> ** **
> Just last week I had to replace a 210. It was getting so hot you couldn't
> touch it. It was putting such a load on the Jeti that it shut down in the
> air. The bearings feel fine, so it may be the magnets. Can magnets cause
> this to happen?. Oh and a year or so ago I did replace the shaft in mine
> and it had just a hair of end play.****
> ** **
>  ****
> ** **
> On Thu, May 2, 2013 at 10:13 AM, John Pavlick <jpavlick26 at att.net> wrote:*
> ***
> You had to rebuild an electric motor? I thought they never wore out (which
> is why they’re better than glow engines)… LOL****
>  ****
> Seriously, how long do magnets last in these big motors (if you’re careful
> about heat + current draw)? Does anyone offer a “magnet-zapping” service?*
> ***
>  ****
> John Pavlick****
> Cell: 203-417-4971****
>  ****
> ****
> Integrated Development Services****
>  ****
> *From:* nsrca-discussion-bounces at lists.nsrca.org [mailto:
> nsrca-discussion-bounces at lists.nsrca.org] *On Behalf Of *Kirk Sutherland
> *Sent:* Saturday, April 27, 2013 11:14 AM
> *To:* NSRCA
> *Subject:* [NSRCA-discussion] Himax 6330 rebuild****
>  ****
> I have rebuilt a Himax 210 . When I  replace the retaining bolt in the
> back how much end play should the can have in it when moved front to back ?
>
> Thanks Kirk
>
>  ****
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