[MRCA] T-195B and volts

[B. Smith]

I was curious and measured the 400 cycle output  frequency of one of my  
T-195 low voltage dynamotors.
On my set:
22 volts =405 cycles
26 volts= 430 cycles
30 volts= 455 cycles

Z




On 9/28/2015 5:08 PM, Ray Fantini wrote:
> AC synchronous choppers, the hart of auto tune discriminators are very frequency sensitive. What may be happening is not an issue of voltage but of frequency. The solid state replacement inverters in the later models may produce a more tolerant 400 cycle source for the choppers then the old dynamotors and perhaps the old dynamotor versions tended to change frequency beyond the tolerance range of the choppers due to poor regulation or sag when keying the transmitter. Remember that frequency of the output of the dynamotor is directly proportional to the speed of the motor itself.
> Radios like the ARC-38 and the 180L automatic antenna tuners use the choppers and they were tolerant of working only with in about 20 cycles above or below 400 cycles, I am assuming the 400 cycle source in the T-195 is one of the dynamotors and not a solid state inverter.
>
> Ray F
>
> -----Original Message-----
> From: mrca-bounces at mailman.qth.net [mailto:mrca-bounces at mailman.qth.net] On Behalf Of B. Smith
> Sent: Monday, September 28, 2015 3:33 PM
> To: grasshopper; mrca at mailman.qth.net
> Subject: Re: [MRCA] T-195B and volts
>
> First things first, I would look at all power supplies especially the
> 400 cycle system, check servo power supply input and output voltage and look at the 400 cycle wave form , maybe the 400 cycle wave form is getting chopped up at lower voltages. But don't expect a nice sine wave but look for it to be consistent in frequency etc.
> Z
>