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 Post subject: RCA 45EY-3 filament voltages
PostPosted: Sep Tue 03, 2019 8:44 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 7323
Location: Toledo, Ohio
Seems like I cannot get the correct voltages on my filaments. I get the 85 volts across the motor windings at a input voltage of 100 volts. Consequently, the voltage across the 25L6 is only 14 volts and 4 across the 6SQ7. The dropping resistor for the filaments measures 26 ohms and is placed between pin 8 of the 6SQ7 and B-. The tube pins and socket pins have all been cleaned.

Of course if I increase the incoming voltage I will eventually get the proper voltages for the filaments but also exceed the rating of the motor windings. I was thinking aboiut replacing the motor with one out of a RP190-4 changer which has a motor rating of 100 volts. Thoughts?

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Jim
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"AC volts and DC volts and little lamps and lities..."


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 Post subject: Re: RCA 45EY-3 filament voltages
PostPosted: Sep Wed 04, 2019 12:04 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 4433
Location: Boston, MA USA
Run the set at the proper voltage (120V is ideal). It is critically important that the motor not be run under-voltage -- it will run very hot and may burn out. What is important is that the series string runs at 300 mA, whatever voltage that entails.

-David


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 Post subject: Re: RCA 45EY-3 filament voltages
PostPosted: Sep Wed 04, 2019 12:29 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 7323
Location: Toledo, Ohio
The motor is not running under voltage. It is running at 85 VAC per specs at 100 VAC input. At that voltage the 25L6 and 6SQ7 filaments are under voltage. Raising the input above that to increase the filament voltage will overvolt the motor.

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Jim
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"AC volts and DC volts and little lamps and lities..."


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 Post subject: Re: RCA 45EY-3 filament voltages
PostPosted: Sep Wed 04, 2019 2:51 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 5990
Location: Minneapolis, MN USA
Jim,
Can you link to a schematic or at least say the source (Riders, Nostalgia Air, Beitmans, etc) ??
Where are you getting 85vac spec for the motor from ?

The schematic I find is for 45EY (not 45ey-3) and the motor is directly across the 115 ac line.


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 Post subject: Re: RCA 45EY-3 filament voltages
PostPosted: Sep Wed 04, 2019 3:26 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 4433
Location: Boston, MA USA
Run it at full voltage. The motor will be fine. I suspect you'll find that once you have correct voltage on the 25L6 heater its resistance will increase.

Many RCA 45 sets connected the motor in series with tube heaters. There were variants with two tubes like this one with an 85V motor (my 6-EY-3A is one of those), or one tube with a 90V motor. The most common configuration like the 45-EY-2 used three tubes with a 115V motor in parallel with the series heater string.

-David


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 Post subject: Re: RCA 45EY-3 filament voltages
PostPosted: Sep Wed 04, 2019 3:05 pm 
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Joined: May Sat 06, 2006 4:03 am
Posts: 3606
Location: ZIP 23831 South of Richmond, VA 25 miles down the pike.
Link to schematic. Dotted area alternate.

Bill J.

https://app.box.com/s/b2yx3jd0t8p7s1anlqrr


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 Post subject: Re: RCA 45EY-3 filament voltages
PostPosted: Sep Wed 04, 2019 9:25 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 7323
Location: Toledo, Ohio
In my first response I should have said that the motor was running at 85VAC per specs with ONLY 100VAC in. I went up to 120 VAC input and got the 25L6 up to 20.5 volts across the filament and 6SQ7 at 5.7 VAC. The voltage across the motor was running 98 volts. I hesitate to run the motor at a higher voltage than stated in the manual.

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Jim
KE8GMW
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"AC volts and DC volts and little lamps and lities..."


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 Post subject: Re: RCA 45EY-3 filament voltages
PostPosted: Sep Thu 05, 2019 12:04 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 5990
Location: Minneapolis, MN USA
Doesn't add up....

Input is 120 vac

Motor =98 vac
25L6=20.5 vac
6SQ7=5.7 vac
Total =124.2 vac
Also doesn't include voltage drop across the resistor


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 Post subject: Re: RCA 45EY-3 filament voltages
PostPosted: Sep Thu 05, 2019 1:22 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 4433
Location: Boston, MA USA
That’s because the motor is an inductive load and the voltage and current are out of phase. The motor is fine.

-David


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 Post subject: Re: RCA 45EY-3 filament voltages
PostPosted: Sep Thu 05, 2019 1:30 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 7323
Location: Toledo, Ohio
dberman51 wrote:
That’s because the motor is an inductive load and the voltage and current are out of phase. The motor is fine.

-David


So you are saying that bringing up the unit voltage to get proper filament voltage will not damage the motor windings regardless of the voltage across it? I can't wrap my head around that.

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Jim
KE8GMW
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"AC volts and DC volts and little lamps and lities..."


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 Post subject: Re: RCA 45EY-3 filament voltages
PostPosted: Sep Thu 05, 2019 1:31 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 4433
Location: Boston, MA USA
It is operating exactly as designed.

-David


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 Post subject: Re: RCA 45EY-3 filament voltages
PostPosted: Sep Mon 30, 2019 9:11 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 7323
Location: Toledo, Ohio
I ended up using a 22 ohm 5 watt dropping resistor and the voltages fell into place. After installing a replacement cartridge I now have a working 45 player.

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Jim
KE8GMW
------------------------
"AC volts and DC volts and little lamps and lities..."


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