[Milsurplus] TCK power supply...

[George Babits]

Ken,

If that transformer puts out 2500 volts,  just wire it for 220 volts with 
the two primaries in series.  Then run 115 into it.  You will get 1250 
volts, give or take.  Then feed that to a bridge rectifier with capacitor 
input filter and you should see around 1700 volts which ought to be close 
enough for what you are doing.

73,
George
W7HDL


----- Original Message ----- 
From: "Kenneth G. Gordon" <kgordon2006 at frontier.com>
To: "WA5CAB--- via Milsurplus" <milsurplus at mailman.qth.net>
Sent: Saturday, April 15, 2017 11:59 AM
Subject: Re: [Milsurplus] TCK power supply...


On 15 Apr 2017 at 13:13, WA5CAB--- via Milsurplus wrote:

> They were most likely not intended for use with a bridge rectifier.

Yes. That is correct.

> If the center tap insulator is smaller than the two end ones, that would 
> be confirmation. If
> it is the same as the other two,

It is.

> that still wouldn't mean that it was, given the 1800 VDC warning.

Yes.

> Is the secondary 2500 CT (1250-0-1250)

Yes.

> or 5000 CT (2500-0-2500)?

No.

> Also, if the rated primary voltage is 115 VAC each winding, 103 VAC on 
> each primary would drop
> the 2500 to 2239, not 1600. If the primaries are 120, then 2146.

They are rated at 115 VAC as printed on the case.

The way I had figured it was that 115 to 2500 would be about 21.74:1 turns 
ratio.
1600/21.74 = about 73.6 volts, so you are correct. It was very late last 
night (midnight) and I
was doing all this in my head, so I obviously made a mistake.

I had figured that I would use a capacitor-only filter after the FWB, so I 
would need 1600
VAC. 1600*1.414= about 2250 VDC out of the rectifiers.

If I stick with 1800 VDC out of the rectifiers, then I would need only 1272 
VAC out of the
transformer, and that would permit full use of the transformer.

At that voltage, I would need only about 83 VAC input to the primary.

Then, since there are two primaries, I could use relays to connect the two 
in parallel for full
power and in series for 1/2 power.

I had calculated for 2250 VDC since the 813 in ICAS service is rated at that 
voltage for full
power input to each tube of 500 watts. For CCS, the rating is 2KV.

However, I anticipate no need to do this. It was simply an exercise in math 
for me. The
difference at the receiving end between 400 watts output, and 750 is less 
than 3 dB, so why
bother?

Anyway, I have two of the transformers. I only need one.

Ken W7EKB

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