EUa4 output voltage

[Dufleuve]

Hello,

Just got a "new" EUa4 with baseplate.

After cleaning and lubricating the dynamotor, it runs perfectly.

Output voltage without charge is 214 volts, I have another that reads 190 volts.
Altough they are both supposed to deliver 130 volts.

How can I test with a dummy charge equals to the UKWEe ?

Thanks

[Funksammler]

The EUa should be delivering 130 V at 26 mA so I make that a 5 kOhm resistance. You should be able to rig up a 5 KOhm 5 Watt resistor across the HV terminals and connect up the starter relay to test the voltage under load. If there are still problems with the Umformer (dirty collector, worn brushes, sparking), I expect you will measure lower rather than higher Voltage. The voltage is slightly sensitive to the 12 V input voltage, on a fully charged battery she might read a little bit higher.

regards,

Funksammler

[Yuri D.]

Ohms law

Resistance = Voltage / Current

If you want the Umformer voltage to drop from 214 to 130, then first start with the amount of current that the Ukw.E.e draws at the plate (Umformer generator output) - should be 26 mA for the plates.

R(plate) = 130 V / 0.026 A

R(plate) = 5000 Ohms

You should use a 3.38 or more Watt resistor. Also, based on my experience, about 190 - 200 volts from an Eu4 = about 140-145 plate volts on the Ukw.E.e. The RV12p4000 tubes can go as high as 190 volts on the plate, so you will be clear there.

You also need to put a load on the filament portion of the Umformer's power - and that will slow it down more

The filament + scale illumination lamp consume 1.54 Amps

R(filament) = 12.6 V / 1.54 A

R(filament) = 8.18 Ohms

Also use at least a 20 Watt resistor or the heat will not dissipate and the resistor will start burning.

If anyone has additional clarification or information, please let us know.

Yuri

[Yuri D.]

The EUa should be delivering 130 V at 26 mA so I make that a 5 kOhm resistance. You should be able to rig up a 5 KOhm 5 Watt resistor across the HV terminals and connect up the starter relay to test the voltage under load. If there are still problems with the Umformer (dirty collector, worn brushes, sparking), I expect you will measure lower rather than higher Voltage. The voltage is slightly sensitive to the 12 V input voltage, on a fully charged battery she might read a little bit higher.

regards,

Funksammler

Maybe I'm wrong - isn't it 26mA per tube, and there are 7 tubes?

Yuri

[Funksammler]

Hi Yuri,

you got me doubting the current, so I checked the Merkblatt for both the Ukw.E.e and the EU.a. The Ukw.E.e is listed as taking 20-25 mA, the Umformer supplying 27 mA HT. This correspondents to what I have got on the date plates of my EU.a's.

regards,

Funksammler

[Funksammler]

Sorry typo, 26 mA...

[Yuri D.]

You are right. The Anode current is 3 mA per tube. I modified the above statement to reflect this.

Yuri

[Dufleuve]

Hello experts .

Tested with a 5 Kohm and it is now delivering 140 volts under load.
Tested with a UKWEe and it works fine.

Thanks to both of you.

[Funksammler]

Congratulations!