[Amps] transformer from dielectric heater tspa

[John T. M. Lyles]

I checked at home, and my WT LaRose dielectric preheater uses the 
5868 triode. It is a THERMALL model 9, about 2.5 feet tall. It has a 
plate current maximum (trip out relay) at 450 mA. Perhaps this is 
similar to the one Larry has a transformer from. In any respect, that 
tube is rated for 450 watts of dissipation, and the various 
datasheets for the TB4-1250 version and the 5868 Amperex version show 
~0.5 Amps of plate current at 4 kVDC. I would then make a guess that 
the THP-4 transformer is in this range of current rating. It may have 
run slightly higher voltage, but the current shouldn't go up much.

73
John
K5PRO

>  >Date: Sun, 7 May 2006 16:50:54 -0500
>  >From: "Larry Carman" <lncarman at swbell.net>
>>Subject: [Amps] thp-4 HV transformer
>>To: <amps at contesting.com>
>>I picked up a very old HV transformer, in good condition, which came from a
>>RF heater which ran a 5868/TB4-1250 tube. The model number on the
>>transformer is THP-4. I have no idea who manufactured it or when it was
>>made. Maybe someone can tell me more about it?  When I connect 240 to the
>>primary I get a .45 amp primary current draw with no load on secondary.  Is
>>this typical for very old transformers?  The secondary is center-tapped with
>>? the secondary winding above the other ? on the core. I get about 4700 VAC
>>from center tap to either of the other secondary legs. It weights 46 lbs.
>>Maybe this would be a good HV trans for a 4-1000 tube. Any help identifying
>>this dinosaur would be appreciated.
>>
>>Regards,
>>
>  >Larry N5BIP