[ARC5] SCR-274N Dynamotor Question

[MARK DORNEY]

Has the dynamotor had any maintenance done to it?  Cleaning and lubrication. 

Mark D. 
WW2RDO 

“In matters of style, float with the current. In matters of Principle, stand like a rock. “.   -   Thomas Jefferson 

Sent from my iPhone

> On Feb 4, 2022, at 9:35 PM, J Mcvey via ARC5 <arc5 at mailman.qth.net> wrote:
> 
> 
> Is the drop at the supply or the radio end? The Tx dynamotor draws about 10 A when it's running, but maybe 30 amps to start it. 50 amps should run the system OK, that's what I use. 
> I used a 8 ft run of 10 awg wire for Tx power.
> 
> On Friday, February 4, 2022, 08:38:10 PM EST, Mark K3MSB <mark.k3msb at gmail.com> wrote:
> 
> 
> I'm working on a new 28V power supply for my SCR-274N system as well as other projects.
> 
> I'm using a 28-0-28 V 50A Transformer with a bridge rectifier (so I'm not using the CT).   I'm using a 220V 16A Variac to set the primary voltage.
> 
> When the setting set for 28V key up,  I'm getting about a 4 to 5 volt drop key down.    
> 
> I didn't expect that much voltage drop as the transformer is pretty stout for an SCR-274N.
> 
> Can I run the system on 30 to 32V key up without damaging the dynamotor?  
> 
> This would be a short term fix as I suspect I'll need a VR circuit.
> 
> 73 Mark K3MSB
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