I have a Pro-Ject Debut Carbon with the AC motor. I just noticed that the power supply provided is putting out 19.4 volts AC according to my DMM. Per the TT manual (and the PS Label itself), it should be 15 volts AC. It’s a synchronous motor, but does the higher voltage impact the motor in a way that affects performance? Speed seems fine, but what about hum or vibration? Seems pretty far off in voltage.
Just curious.
Just curious.
If its not affecting speed or hum then I wouldnt worry.
Its 25% out which is a bit but probably nothing to worry about.
Its 25% out which is a bit but probably nothing to worry about.
The 19.5v you are measuring with no load, when the supply is under load you may find it is lower.
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Synchronous motor -synchronized to the frequency of the supply current -
USA=60Hz ---UK =50Hz -
Synchronous motor - Wikipedia
USA=60Hz ---UK =50Hz -
Synchronous motor - Wikipedia
Like a lot of other Debut owners, I had a hum problem that I largely fixed with sorbothane pads on the motor mount. But it still occasionally hums. I finally stuck the DMM on it and saw the high reading and wondered it it was a contributor. I was considering replacing the wall wart with a better one, although I really think it’s a vibration sound rather than an electrical hum. I bet these motors just aren’t as well-balanced as they need to be. Thanks for the thoughts.
AC motors are prone to physical hum because the windings vibrate. A higher voltage will result in more coil energy. The energy in the coil becomes torque. An experiment you can try is to lower the voltage with a series resistor. Choose appropriate power rating. Is it possible to lower the voltage to a point where speed is retained with sufficient torque?
Depending on the motor construction it may be possible to damp the housing with Dynamat. Dynamat may also be used on the underside of the plinth to absorb some of the energy. It is messy stuff, but works.
Depending on the motor construction it may be possible to damp the housing with Dynamat. Dynamat may also be used on the underside of the plinth to absorb some of the energy. It is messy stuff, but works.
While it is correct to say AC motors vibrate/hum that is relative .
Cheap two pole motors are the worst probably unbalanced , static balance is not used solely dynamic balance .
Inaccurate balance in two planes at least causes hum/vibration ,this is also tied up to the enclosure /frame of the motor (if any exists) where the vibration is transmitted to the rest of the deck.
I have an expensive 24 pole motor fully enclosed and shielded but even here there is a special type of insulator at its base.
Its expensive for a manufacturer to buy in /manufacture high quality motors even on a production line basis which wouldn't normally apply to high end hand built decks.
If you have the money for a high end deck don't just look at the arm/cartridge /build ask about the drive motor specifications.
Cheap two pole motors are the worst probably unbalanced , static balance is not used solely dynamic balance .
Inaccurate balance in two planes at least causes hum/vibration ,this is also tied up to the enclosure /frame of the motor (if any exists) where the vibration is transmitted to the rest of the deck.
I have an expensive 24 pole motor fully enclosed and shielded but even here there is a special type of insulator at its base.
Its expensive for a manufacturer to buy in /manufacture high quality motors even on a production line basis which wouldn't normally apply to high end hand built decks.
If you have the money for a high end deck don't just look at the arm/cartridge /build ask about the drive motor specifications.