[time-nuts] OT - DC-10 gyros

Robert Atkinson robert8rpi at yahoo.co.uk
Thu Mar 28 08:20:16 EDT 2013

Hi Bill,
The amp I used was similar to this circuit http://www.circuitstoday.com/100w-mosfet-power-amplifier which is a common design. Supply is 45V (unregulated rectified and filtered 30V transformer) so will drive 26V out OK.
I've also used modules from ILP in the past, sometimes with a step-up transformer. To be honest even a square wave chopped up 35V DC would probably work OK for these little rate gyros, but they are quieter on a sinewave.
Robert G8RPI.

From: Bill Ezell <wje at quackers.net>
To: time-nuts at febo.com 
Sent: Thursday, 28 March 2013, 11:18
Subject: Re: [time-nuts] OT - DC-10 gyros

It's almost certainly part of the flight stability / autopilot system, as suggested privately by another time-nut.
The gyros spin up nicely and run quietly, so sounds like the bearings are fine.

I was using an old Yamaha amplifier I had around for the 400Hz drive. I think I'm going to go the audio amp route. The biggest problem I'm having with replacing it is that I haven't found a small amp yet that has enough output voltage. I'm going to breadboard up something tonight - simple phase-shift oscillator driving a pair of FETs in class B configuration with a low-pass filter to clean things up. It actually doesn't have to be all that clean. The gyros are electromechanical devices after all, they're just little split-phase AC motors.

As for what I'm going to do with it, why, the same thing we do with our time and frequency related projects - play with it. :) My goal is to get the electronics package fully functional. Fortunately, everything is analog using transistors you can actually see and quad 741 op-amps in real dip packages, and even better, only double-sided pc boards.

On 03/27/2013 11:16 PM, time-nuts-request at febo.com wrote:
> Is this part of an HSI (horizontal situation indicator), ADI (attitude
> director indicator), INS (inertial navigation system), or autopilot?  Are
> the bearings dust?
> Sounds like fun to play with though.  What do you plan to do with it?

-- Bill Ezell
They said 'Windows or better'
so I used Linux.

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