Choke question(s)

[KB2WIG]

I'm currently doing up a pwr supply for an ATC.. Looking closer at the choke tag, what i thought was a  2500V rating, is the TEST voltage.... My question(s) is --can I use this thing in my 1300V supply??? Is the 10V rating the drop accross the choke?  Do I tempt fate and us it anyway?  Will I k1man return?        the tag reads            Stewart-Warner 571587    10H,   0.5A,   10V, 60cps                     TF1AO4YY  Chicago Transformer, Div of Essex Wire Corp., Chicago......  with all this info, and then Googlin  I cant find much information , with the exception of car parts......   klc

[WA2IXP]

I think the 10v and 60 cyc. is the manufacturers test standards that they used to determine the rating of 10H. I'm not sure though.  It would probably work at 1300v but why not put in the negative lead of rectifier so its not  subjected to hv between windings and core? just some thoughts jay-

[WA1HZK]

Every time i use the old iron I slide an insulator under it and do not bolt the frame to ground. Why tempt fate? You do understand Murphy's law of random perversity?

[W2PFY]

Have you considered negitive lead filtering? Takes away the breakdown voltage problem.

[W2VW]

Negative lead filtering works great but be sure to use a spark gap across the choke if your rectifier is a full wave center tap type. Many center tapped plate transformers don't have a very high hi-pot rating at the center tap and the spike from a choke being shut off quickly will break insulation down. 

[k4kyv]

Negative lead filtering works great but be sure to use a spark gap across the choke if your rectifier is a full wave center tap type. Many center tapped plate transformers don't have a very high hi-pot rating at the center tap and the spike from a choke being shut off quickly will break insulation down.

Even the spark gap may not give adequate protection.  You may have only 10 volts DC voltage drop across the choke, but the peak value of the induced AC voltage across the choke may approach the value of the DC output voltage.  The full AC ripple voltage of the unfiltered DC at the output of the rectifier is dropped across the choke.

I would put the choke in the positive side, but insulate it from ground.  Just don't touch it while the power supply is in operation, since you might get zapped with the full DC voltage if the coil happens to short to the core while you are in contact with it.

[KB2WIG]

Thanks for the input. I guess ill go with a pie configuration with the choke isolated from gnd in the HV leg. I've got (2) 10uF 2KV caps for each side of the choke..       
-Got (2) 21.3 uF 5KV caps... for the modulator current.... we will see if the smoke stays inside.....     klc