[ARC5] SCR-274N Dynamotor Question

[Robert Downs]

No.  Set it for 28VDC key up.  32 VDC would put 16 VDC on each of the 12.6 V rated tube filaments which will significantly shorten their service life

 

Robert Downs

 

From: arc5-bounces at mailman.qth.net [mailto:arc5-bounces at mailman.qth.net] On Behalf Of Mark K3MSB
Sent: Friday, February 4, 2022 19:38
To: ARC5
Subject: [ARC5] SCR-274N Dynamotor Question

 

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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