3 Sep
2014
3 Sep
'14
2:46 p.m.
I replace all of mine with these caps I found on amazon:
http://www.amazon.com/dp/B009IMR5UO/ref=pe_385040_30332190_TE_3p_M3T1_ST1_d…
They're higher voltage and the diameter is slightly less than the originals
so they will fit without modifying the chassis. I haven't had any problems
with them (yet).
Best of all they're filled with Chinese "Vegetable oil", yum.
Marc
On Wed, Sep 3, 2014 at 1:35 PM, Rik Bos <hp-fix at xs4all.nl> wrote:
Yes, mains frequency determines the rotation speed of
the field. Rotor
speed is a little slower so there is current inducted in the rotor 'cage'
which creates a another field. This field is forced to follow the mains
field. Because there is a little speed difference 'slip' between the stator
field and and the rotor speed. Those motors are called asynchronous, slip
is between 2-6% depending of the size of the motor and power needed.
This goes for 1 and 3 fade machines both have rotating fields.
-Rik
-----Oorspronkelijk bericht-----
Van: "Paul Koning" <paulkoning at comcast.net>
Verzonden: ?3-?9-?2014 22:12
Aan: "General Discussion: On-Topic and Off-Topic Posts" <
cctalk at classiccmp.org>
Onderwerp: Re: TU56 Motor Run Capacitors.
?Asynchronous??
Run caps are found in AC induction motors fed by a single phase power
source, whether electronic or not. If you have an actual multi-phase power
source (3 phase mains or a multi-phase motor controller) then there is no
run cap.
paul
On Sep 3, 2014, at 3:08 PM, Rik Bos <hp-fix at xs4all.nl> wrote:
Ok an asynchronous motor, no electronics
involved.
-Rik
-----Oorspronkelijk bericht-----
Van: "Camiel Vanderhoeven" <iamcamiel at gmail.com>
Verzonden: ?3-?9-?2014 20:53
Aan: "General Discussion: On-Topic and Off-Topic Posts" <
cctalk at
classiccmp.org>
Onderwerp: Re: TU56 Motor Run Capacitors.
And of course, Wikipedia can be helpful:
(from http://en.wikipedia.org/wiki/Motor_capacitor)
Run capacitors
Some single-phase AC electric motors require a "run capacitor" to
energize the second-phase winding (auxiliary coil) to create a
rotating magnetic field while the motor is running.[3]
Run capacitors are designed for continuous duty while the motor is
powered, which is why electrolytic capacitors are avoided, and
low-loss polymer capacitors are used instead. Run capacitors are
mostly polypropylene film capacitors and are designed for continuous
duty, and they are energized the entire time the motor is running.[1]
Run capacitors are rated in a range of 1.5 to 100 microfarads (?F or
mfd), with voltage classifications of 370 V or 440 V.[1]
If a wrong capacitance value is installed, it will cause an uneven
magnetic field which causes the rotor to hesistate at those spots that
are uneven, which can be observed as uneven motor rotation speed,
especially under load. This hesitation can cause the motor to become
noisy, increase energy consumption, cause performance to drop, and
cause the motor to overheat.[3]
On Wed, Sep 3, 2014 at 8:29 PM, Camiel Vanderhoeven <iamcamiel at gmail.com>
wrote:
> I believe they're plain capacitors;
bipolar, non-electrolytic. Those
> are a bit more difficult to find.
>
> On Wed, Sep 3, 2014 at 7:47 PM, Rik Bos <hp-fix at xs4all.nl> wrote:
>> 100uF/100V or 63V aren't especially rare.
>> Those are just normal value's or are they bipolar types?
>>
>> -Rik
>>
>> -----Oorspronkelijk bericht-----
>> Van: "Robert Adamson" <bob at theadamsons.co.uk>
>> Verzonden: ?3-?9-?2014 16:34
>> Aan: "cctech at classiccmp.org" <cctech at classiccmp.org>
>> Onderwerp: TU56 Motor Run Capacitors.
>>
>> I'm refurbishing a TU56 and of course the tape drive motor capacitors
are completely shot. They're 100uF and only need to be about 60-80V to be
quite safe (originals 100uF/55V) but I can only find capacitors rated for
450V which is no big issue except for their size.
>>
>> I'm thinking of using motor start capacitors. They're only rated
intermittent but I feel that the derating to around 60V should probably
give them a good lifetime. Views?
>
> Bob