TEN-TEC POWER TRANSFORMER

[W8UJX]

Just lost the power transformer in my Centurion 422 amp.  Primary to secondary short.  What is the best route to go to repair/replace this beast?

Thanks,
Jerry, W8UJX since 1954

[WA1GFZ]

have gary the transformer guy rewind it

[W3GMS]

Just lost the power transformer in my Centurion 422 amp.  Primary to secondary short.  What is the best route to go to repair/replace this beast?

Thanks,
Jerry, W8UJX since 1954

Jerry,
Same thing happen to my Ten Tec Titan Amp.  When the HV winding shorted to the low voltage winding it took both of the 3CX800's.  I really don't like Ten Tec's approach of mixing very high voltage windings with lower voltage windings.  To me they don't use enough insulation between the windings and they ultimately short.  So not only do I need a new xmfr but two new tubes.  I wish Peter Dahl was still in business since his xmfr's were nearly bullet proof.  Many Titan owners have gotten rid of the Ten Tec transformers and used the Dahl replacement with no further problems. 
Good luck...
Joe, W3GMS 

[n4wc]

Tom Hand, W4WDS rewound my TenTec Centurion transformer after it shorted primary to secondary.  He used Nomex instead of fishpaper.  After he was finished it would do 1.5 amps CCS.  Still working great after 3 years.  Tom is located near Demorest, GA, northeast of Atlanta a ways.

[W2NBC]

Not sure about the Centurion, however the Titan T1 is still listed under the Harbach Electronics /Peter Dahl Company

http://www.harbachelectronics.com/_mgxftp/pwdamateur/PWDAMATEURT.PDF

http://www.harbachelectronics.com

[W8UJX]

Thanks Joe,

The power transformer in the Ten Tec Centurion is a dedicated HV transformer.  The HV winding feeds a voltage doubler made up of twenty 1 KV, 6 amp diodes and eight 220 uF, 450 volt caps in series.

The filament supply for the two 3-500Z tubes is on a separate transformer.

Gary wants $345 to rewind it plus I'm in CA so there would be a hefty postage cost.

I'm retired and on a fixed income.  I was hoping someone out there might have something in their junkbox.  Hi...

Jerry, W8UJX since 1954

[W3GMS]

Tom Hand, W4WDS rewound my TenTec Centurion transformer after it shorted primary to secondary.  He used Nomex instead of fishpaper.  After he was finished it would do 1.5 amps CCS.  Still working great after 3 years.  Tom is located near Demorest, GA, northeast of Atlanta a ways.

Bill,
Thanks for the lead on a good re-winder.  Maybe I will get a price from him and Gary.  I know Gary does an excellent job as well.  Sounds like a good "road trip" from up here in S.E. PA...!  Visit some Hams on the way to make it a fun trip.
Joe, W3GMS 

[W3GMS]

Not sure about the Centurion, however the Titan T1 is still listed under the Harbach Electronics /Peter Dahl Company

http://www.harbachelectronics.com/_mgxftp/pwdamateur/PWDAMATEURT.PDF

http://www.harbachelectronics.com

Thanks Jeff for letting me know.  If they are built to the same spec's as Peter Dahl's, I am sure they would last a long time.  Will have to price a good rewind job compared to a completely new xmfr. 

Joe, W3GMS

[W3GMS]

Thanks Joe,

The power transformer in the Ten Tec Centurion is a dedicated HV transformer.  The HV winding feeds a voltage doubler made up of twenty 1 KV, 6 amp diodes and eight 220 uF, 450 volt caps in series.

The filament supply for the two 3-500Z tubes is on a separate transformer.

Gary wants $345 to rewind it plus I'm in CA so there would be a hefty postage cost.

I'm retired and on a fixed income.  I was hoping someone out there might have something in their junkbox.  Hi...

Jerry, W8UJX since 1954

What secondary voltage are you looking for?  I will assume your using 230 primary voltage. 
I think your amp has the iron built in the amp itself.  If you used some old buzzard xmfr, I am sure it would be larger and likely have to be outboard from the amp.  Is that ok with you? 

Joe, W3GMS

[W8UJX]

Joe,

The transformer was mounted inside the amp chassis.  No load voltage is 2300 VAC, 115/230 VAC primary.

I was thinking about using an old out board transformer.  I have several large transformers that go up to 3 KV but they only have 115 VAC primaries.

I don't think those old tube type transformers would have very good regulation.  The plate voltage in my Globe King is 1800 VDC under load but I think it goes up to about 2700 volts key up.

I was thinking of connecting one of those old transformers to the voltage doubler circuit in the Centurion but I would have to be carefull that the no load voltage did not exceed the rating of the filter caps.

Worst comes to worst I could build a plate supply from scratch.  I have all the parts in the junk box, big honkin transformer, pair 866's etc and enjoy the blue glow at night.  Hi...

Jerry, W8UJX since 1954

[K5UJ]

I own a Centurion I use routinely on AM.

The no load B+ is 3100 v.   Sags to around 2800 under load.

The stock h.v. transformer shorting in one way or another is a known issue.   I now run an 85 lb 1.5 A outboard transformer with mine.   The stock iron is 500 ma 115 0 115 primary 0 - 2250 secondary.

There is no voltage doubler only four strings of 6A10s five each to make a FWB rectifier.  Caps have changed over the years; mine has 8 or 9 lytics 450 v. 330  uF. 

> I really don't like Ten Tec's approach of mixing very high voltage windings with lower voltage windings.

I don't know what this means.  What plate iron does not have a low v. primary?  Or if you mean filament etc. windings there are none on the Centurion ; it has a separate fil. supply transformer.

Rob

[W3GMS]

I own a Centurion I use routinely on AM.

The no load B+ is 3100 v.   Sags to around 2800 under load.

The stock h.v. transformer shorting in one way or another is a known issue.   I now run an 85 lb 1.5 A outboard transformer with mine.   The stock iron is 500 ma 115 0 115 primary 0 - 2250 secondary.

There is no voltage doubler only four strings of 6A10s five each to make a FWB rectifier.  Caps have changed over the years; mine has 8 or 9 lytics 450 v. 330  uF. 

> I really don't like Ten Tec's approach of mixing very high voltage windings with lower voltage windings.

I don't know what this means.  What plate iron does not have a low v. primary?  Or if you mean filament etc. windings there are none on the Centurion ; it has a separate fil. supply transformer.

Rob

Rob,
I was referring to other lower voltage secondary windings an not the primary voltage since every transformer needs a primary!  Here are the multitude of secondary voltages on the Titan transformer: 

TEN-TEC 425 TITAN POWER XFMR T1, MAIN POWER TRANSFORMER
CORE) A-0480/ C-CORE STYLE #) 10 HIPERSIL C-CORE
PR) 120/240 VAC 50/60 HZ 1 PH
S1) 1270 VAC @ 1.0A CCS
S2) 570 VAC @ 1.0A CCS
S3) 13.5 VAC @ 6A CCS
S4) 20 VAC @ 6A CCS
S5) 20 VAC @ 2A CCS
DM) HT = 7.625 WT = 8.075 DT = 7.688 MD = 3.937 MW = 5.500 WEIGHT) 46 LBS   

Those many secondary windings, together with inadequate insulation results in a high failure rate between windings.  Formerly Dahl and now Harbach has a good replacement that does have adequate inter-winding isolation and thus no problems.   

Joe, W3GMS   

[W8UJX]

Hi Rob,

Yea, I screwed up.  It is a full wave bridge circuit.

Jerry, W8UJX

[K5UJ]

Jerry no prob.  Joe, I should have realized what you meant, sorry.  don't know zip about the Titan.  surprised TT did that with all the windings.  Centurion has nothing but h.v. winding on secondary.  story I heard (not verified) years ago they used Dahl but got cheap and made their own in-house, then their tranny guy retired or quit and they got them from some outfit in Canada & that's when users started experiencing failures. 

rob