[ARC5] Power Supplies, DC-DC inverters & co

Tue Sep 29 21:16:28 EDT 2015

I looked at the spec for the DM33 dyno. It's 575 @ 160ma (92W) continuous,  540 at 250ma intermittant (135W)THe DM33 also powers the modulator, which I don't have on my home-brew supply.Also after some more Ebay dredging, I found this:http://www.ebay.com/itm/12V-to-DC450V-150W-high-voltage-converter-boost-step-up-power-capacitance-charge-/151810143780?
|   |
|   |  |   |   |   |   |   |
| 12V to DC450V 150W high voltage converter boost step up ...US $22.99 New in Consumer Electronics, Multipurpose Batteries & Power, Travel Adapters & Converters |
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| View on www.ebay.com | Preview by Yahoo |
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|   |

In both cases, I may be able to put them in tandem like your did and adjust them for 575v if the outputs are isolated. 
However, I get the feeling that this is a Boost type regulator, which would NOT be isolated.I ordered the first 70W one I posted ( I found the same one for $11 also selling on Ebay).There are also smaller ones that would still work well for the receivers.

The other way to approach the problem of low/sagging B+ would be to put a boost reg between the battery and the SCR274 to keep the dyno speed steady.I like the SMPS Dyno replacement approach for two reasons: 1) It's a heck of a lot more efficient 2) saves the dynamotors for demonstrations instead of daily use.

     On Sunday, September 27, 2015 12:34 AM, Leslie Smith <vk2bcu at operamail.com> wrote:

On the topic of power supplies:  
Don VE3LYX is experimenting with 120V supplies for transmitters.  

He said:  

"Princess Auto had 120W plug in inverters on for $30 so I bought one. I
tested it too see if it would supply my breadboard stations PSU.  Itt
had no trouble handling the load of both P.S.U., receiver and
transmitter key down.  [Here, transmitter means No 19 set.]  I built a
voltage rectifier doubler that plugs into a 120 volt wall plug and
plugged it into the 120w inverter. With a load resistor in the circuit
(bleeder resistor) I had now 318 volts of filtered DC. 

"I wondered what about a pair piggybacked. I built an identical
rectifier doubler but was unable to get an identical inverter.  However
I found one of the same rating for a couple of dollars more and bought
it along with a three in one cigar lighter plug recepticle. 

I lashed-up a circuit and tried each [power supply] separate. All was
good so I piggybacked the right hand doubler with the left hand doubler
(pos to neg) so my right hand is positive and the end of the left hand
neg. I fired it up, wanting to see if they would interact and bother
each other.  (I have used a similar set up for years to supply 500 volts
to an old military set but with vibrator supplies.)  

With a load (bleeder resistors) 624 volts."

Then a few days later Don told me: 

 "I put the new power supply to the ultimate test last night. I fed 
  my No19 Wireless set direct  with it. It was groaning but didn’t 
  crap out. Even had it on transmit. I have noise in the 12v circuit. 
  Not real real bad but objectionable so I will have to try a Hash 
  filter not unlike the vibrator supplies." -  don VE3LYX  

Don's report is current.
Interesting, I think.
  73 de Les Smith
  vk2bcu at operamail.com

On Sun, Sep 27, 2015, at 13:06, J Mcvey wrote:
> Dave, et all...Your most made me wonder what other inexpensive dc-dc
> device might be offered on Ebay and I found this:
> 
> |   |
> |   |  |   |   |   |   |   |
> | DC12V 24 to DC 200-450V 70W high voltage converter b...US $14.54 New in
> Business & Industrial, Electrical & Test Equipment, Test Equipment |
> |  |
> | View on www.ebay.com | Preview by Yahoo |
> |  |
> |   |
> 
> http://www.ebay.com/itm/DC12V-24-to-DC-200-450V-70W-high-voltage-converter-boost-power-supply-with-shell-/181770613759?hash=item2a525f73ff
> 
> It might work out as a sub for the dynamotors. I am hoping that it will
> be marginally sufficient as a transmit supply, at least it will have
> better regulation...
> 
> 
> 
>      On Saturday, September 26, 2015 9:38 PM, David Stinson
>      <arc5 at ix.netcom.com> wrote:
>    
> 
>  P.S. Here's one of the little DC-DC converters.
> I use these things for lots of stuff.
> Had a few little birdies but nothing that caused
> me any trouble.  Here's one; there are many
> available and prices vary all over.
> Some are less than $2.
> 
> http://www.ebay.com/itm/261078380110
> 
> They make them in "Boost" models as well.
> They're ground/negative common in and out,
> so not for applications where you need isolation.
> 
> If you'd rather use a linear regulator:
> 
> http://www.ebay.com/itm/361396441422
> 
> Used these with good results as well.
> 
> 73 Dave S.
> 
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