What voltage do you use?

Re: What voltage do you use?

Postby krokodil » Sun Jul 12, 2015 1:57 pm

Here is a simple circuit to test the DCC voltage in tracks. The instrument connected to the output should a simple DC voltmeter ( not an AC).

(Sorry on this device i do not have a better drawing tool.)
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DCC detector
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Re: What voltage do you use?

Postby ConducTTor » Sun Jul 12, 2015 2:02 pm

Sorry, reading electric diagrams is not one of my strengths. Can you tell me what is what in the above?
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Re: What voltage do you use?

Postby krokodil » Sun Jul 12, 2015 2:38 pm

There is one multipurpose diode 1N4148 ( or similar) and a capacitor of about 1 micro Farad ( it can by polarized for 25V or MKT). In case of polarized one, the plus end should go to the marked end ( black ring) of the diode. ( both part are easily available in any electronic part shop like Radio Shack, Digi Key or Fry's. The meter is connected to the right side of the circuit ( 2 terminals). The left side terminals are connected to the tracks.

This circuit is connected between the track and the instrument.
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Re: What voltage do you use?

Postby ConducTTor » Sun Jul 12, 2015 3:06 pm

Thank you!
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Re: What voltage do you use?

Postby krokodil » Tue Jan 19, 2016 2:24 am

Recently I got a phonecall from my friend (owner of a model railway service shop), that somebody brought him almost a dozen of faulty N models. All were upgraded for DCC with Zimo and Tran decoders, and all had burned motors. All decoders were OK, all motors had some issues - partialy they required 700 mA power to run! (Typical valu is below 200 mA.)
We went out to the owner of the layout and saw that the voltage in some portions of the track was almost 20V! 19,9V). The problem was immediately identified. The booster did not have any internal stabilizer, the owner almost no electrical knowledges and also no measuring instrument.
This voltage is simply too high for the tiny motors. The manufacturer specifies on the box 22V DCC!!! :wall: :wall:
He used simple transformers for 16V what gives after rectification almost 22-24V. If the booster/control unit does not have internal voltage stabilizer, this high voltage kills most of the modern tiny motors.
We replaced his standard transformers with cheap switched power supplies ( used for laptops, LED lights etc) with adjustable output ( 12-19V/3-6A) and adjusted them to 11V voltage in tracks measured with the adaptor described above.
Unfortunately the broken motors cannot be easily replaced (discontinued or very expensive), this means his models now partialy must be machined to fit different motors. It will be a costly repair.

Do not forget! In case of DCC always the lowest working voltage in the tracks is the best selection!
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Re: What voltage do you use?

Postby ConducTTor » Tue Jan 19, 2016 11:29 pm

Oh man that's painful. I bought lower wattage power supplies a while back so I don't end up in the same boat. All 14 volts so at the motor it will be ~12.5 to 13. I hope even that's not too much.
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