Identify electrical component to old mixer

Discussion in 'Community Discussion' started by velocityg4, Nov 27, 2010.

  1. velocityg4 macrumors 68040

    velocityg4

    Joined:
    Dec 19, 2004
    Location:
    Georgia
    #1
    I have a Hamilton Beach Scovill Deluxe mixer model 40-3. The best I can tell is that the resistor is faulty, assuming I've identified the part correctly.

    When removed from the mixer's the speed control will work fine, when installed the mixer runs at full speed all the time. My Ohm meter detects near zero resistance through the component in question.

    I can not identify it as a resistor (it is much larger than any I recall seeing). It rests between the motor and power cord, where the speed controller meets the motor. Yet the speed controller bypasses the resistor. So that one end of the power cord goes to the motor. While the other goes to the speed controller (which appears to use points like in an old car and unlike any rheostat I have ever seen)then on to the motor.

    I attached an image of the part as I can not decipher the text, as it is too degraded. Hopefully someone can figure out what part I need to repair this mixer. The gunk is 40+ year old electrical tape residue. Which is now a hardened shell that I carefully scrapped off with an exacto knife to minimize damage to the underlying hidden text.

    The mixer is from 1968, so yes I know there are better mixers nowadays if I wanted one I would buy a KitchenAID Professional 5 Plus 450 watt mixer. I want to repair it because it would be interesting to repair something that old and use it for the occasional cake or whipped cream, when opened up the motor looks brand new. As does the chrome finish on the outside. It is a rather meek unit using only 150 watts.

    Resistor.jpg
     
  2. TEG macrumors 604

    TEG

    Joined:
    Jan 21, 2002
    Location:
    Langley, Washington
    #2
    It looks to be an old-style pancake capacitor. If you have a store that does electronics repair or a very good Radio Shack might be able to decipher the codes and find a replacement. Failing that, you could local a local college with an Electrical Engineering department, they may have exactly what you need to get it fixed. And they may even use it as a demonstration for a class.

    The only other thing I can think of it to be is a relay, but they typically aren't shaped like that.

    TEG
     
  3. velocityg4 thread starter macrumors 68040

    velocityg4

    Joined:
    Dec 19, 2004
    Location:
    Georgia
    #3
    I think you may be right that it is a capacitor. Now since the mixer runs fine with the capacitor removed. Do I risk damaging the motor by operating without it? Will it simply lessen it's overall torque?

    The markings seems to say the following (x's indicate indecipherable character's)
    x08 MF +/-10% (The + is over the -)
    x40x VAC SUN

    There may have been at one time more than one character in front of the 08 on the first line and possibly one character after the MF.
     
  4. iJohnHenry macrumors P6

    iJohnHenry

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    On tenterhooks
    #4
    Spit-balling here, so easy on the Ye Olde Mouse™.

    Capacitors hold a charge, right?

    Perhaps it holds a kick-start for the motor, so as not to blow a 15 amp fuse. Then it shuts down and forces the current to go through the speed control.

    But as it shows zero resistance, the switch-down part is pooched.

    That's my interpretation for what's going on. :p
     
  5. OutThere macrumors 603

    OutThere

    Joined:
    Dec 19, 2002
    Location:
    NYC
    #5
    Those look like the markings for a capacitor...I expect the MF is the old school way of denoting capacitance in (micro)Farads, nowadays it would be μF. Perhaps matching the capacitance and voltage (if you can clearly decipher the numbers at all) you could match it with a new one.
     
  6. localoid macrumors 68020

    localoid

    Joined:
    Feb 20, 2007
    Location:
    America's Third World
    #6
    It's probably a "run capacitor" instead of a "start capacitor"... see this page for a brief explanation of how run and start capacitors are typically used.

    It might be a 8 MFD 140v capacitor, but you need to identify the exact MFD value for the circuit to work properly. If your volt/ohm measures near zero resistance then it's likely bad (a capacitor normally has infinite or near infinite resistance)...
     
  7. KeriJane macrumors 6502a

    KeriJane

    Joined:
    Sep 26, 2009
    Location:
    ЧИКАГО!
    #7
    Does the arrangement match this drawing?
    If it's across the controller as pictured, it's called "In Parallel"

    If that's across the speed controller, it's probably a capacitor there to clean up interference from the controller and extend the life of the controller by reducing arcing across the contact points. The controller probably won't last long without it.

    Sometimes a capacitor is called a condenser. If it's shorted, it won't be possible to measure the capacity with a meter. You would need a capacitance meter to test it anyway.

    What to do? I would try to find an old-school appliance repair person. Failing that, try googling "Mixer capacitor" "Mixer condenser" "Mixmaster capacitor".

    It's probably pretty cheap once you figure out what kind to get.

    Good Luck,
    Keri
     

    Attached Files:

  8. iJohnHenry macrumors P6

    iJohnHenry

    Joined:
    Mar 22, 2008
    Location:
    On tenterhooks
    #8
    Yes, I believe that is what we are talking about. Nice pic, JJ. :)

    Remember, this machine was made in 1968, when electrical circuits were somewhat more primitive than today. Mostly fuses, and probably 15-amp.

    I still think that if he is on 20-amp service at the plug he is using, he can leave the damn thing disconnected without any risk to his wiring or the device itself.
     
  9. KeriJane macrumors 6502a

    KeriJane

    Joined:
    Sep 26, 2009
    Location:
    ЧИКАГО!
    #9
    Here's my crude, 3-minute interpretation of an oscilloscope reading.

    For reference purposes, imagine a straight line being a constant voltage. This is called DC. If the line rises on the screen, this indicates higher voltage. Left-to-right orientation along the line indicates time, often in milliseconds.
    Appliances run on AC but the effect of switching an inductive load is similar.


    If one were to turn a switch on and off rapidly for a non-inductive load like a light bulb, there are no voltage spikes. The power goes on and off in time with the switch. Kind of like line "A"

    If one does the same thing with an inductive load like a motor, the collapsing magnetic field in the motors windings cause a strong back voltage to be generated. This will very often be much higher than the supply voltage.
    This increased voltage can very easily bridge a gap such as between the contact points of a switch or controller. This will erode the point very quickly.
    Line "B" is my very crude analogy.

    If we bridge the points with a capacitor, it will effectively pass the reverse-voltage spikes right though bypassing the points and reducing the arcing.
    In addition, the back voltage can "push" against the motor, increasing its efficiency. Line "C" is another crude analogy and doesn't tell the whole story.

    A couple of notes:
    My simple drawings reflect a Direct Current (DC) circuit. Alternating Current (AC) already has a rapidly changing sine wave polarity somewhat between line B and C.
    A rapidly switched inductive load on AC is more difficult to illustrate, but the effect is similar.

    Capacitors don't exactly "pass" voltage fluctuations through, but the effect is the same. It's more sort of a rapid "Store-Release" cycle that can store the spikes when they're not wanted for an instant and release them right when the power can be used.

    Have Fun,
    Don't even ask how long it took to learn this stuff,:eek:
    Keri
     

    Attached Files:

  10. velocityg4 thread starter macrumors 68040

    velocityg4

    Joined:
    Dec 19, 2004
    Location:
    Georgia
    #10
    I decided to send an e-mail to Hamilton Beach asking if they have that info on file.

    That diagram is correct.

    I left the cover off and ran the motor for a couple minutes at half speed and full speed. The motor, wiring and all components were still cold to the touch they didn't even rise above room temperature. Perhaps things may change under load. If this is any indication perhaps the capacitor being absent won't have too much of an effect. They did build stuff like a tank in then. Though if I can find out the right one I will install it.
     
  11. Arran macrumors 68040

    Arran

    Joined:
    Mar 7, 2008
    Location:
    Atlanta, USA
    #11
    Try that again with an AM band radio playing nearby. If you hear crackling/interference on the radio then it's most likely an RFI suppression capacitor that's blown. It's common practice to put a small capacitor across switches and controllers to smooth out interference-generating voltage spikes.
     

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