Thanks Steve, that does clarify the situation … so, you are terminating each output with 1k to CAS common.
I do have the older gear-driven CAS with mating EC2 and never had an engine misfire event at WOT or cruise. Did experience some rough running at idle and some cold-start issues – always have to preheat my engine
in the winter to get it started. I was wondering if this new revelation would help with either but alas apparently not.
Jeff
(Still rebuilding: wings done, re-drive looks good, engine has bearing damage plus rear end and center housing damage)
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From:
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"Steven W. Boese" <SBoese@uwyo.edu>
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Subject:
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RE: [FlyRotary] Re: Renesis CAS & EC-2 upgrade? ... Which CAS wire needs the 1K resistor?
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Date:
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Fri, 9 Nov 2012 15:04:19 +0000
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To:
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Rotary motors in aircraft <flyrotary@lancaironline.net>
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Jeff,
If you are using the gear driven distributor style CAS with a controller set up for that, you should not need to add the resistors. I am using two Renesis CAS with
a 12 and a single trigger tooth wheel on the eccentric shaft of a Renesis engine with an EC2 set up for the gear driven CAS. To use this combination, a 1K resistor has been added at the CAS end of the harness between the two connections to each CAS. My reference
to adding a resistor from the CAS to ground may be incorrect. The resistors are added between each CAS output and the CAS return. I have not verified whether CAS return is in fact ground. In effect, a resistor is connected from pin 4 to pin 22 and another
resistor is connected from pin 23 to pin 22. The green wire of my gear driven CAS is not ground .
Steve
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From: Jeff Whaley
Sent: Friday, November 09, 2012 9:38 AM
To: 'Rotary motors in aircraft'
Subject: Re: Renesis CAS & EC-2 upgrade? ... Which CAS wire needs the 1K resistor?
Steve:
Looking at my CAS-to-EC2 wiring diagram, there are Red, White and Green wires connecting to the EC2 at pins 4, 23 and 22 respectively.
Assuming the Green is Ground, are you connecting a 1k resistor across the Red and White wires? – Or are you “Terminating” both the Red and White with 1k to Ground?
Are you doing this inside the CAS, inside the EC2, or adding it to the wire harness?
Please clarify … thanks
Jeff
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Ed,
I tested the engine on the stand with variable resistors across each CAS yesterday. With the engine idling at about 1500 RPM, less than 100 ohms resistance across
either CAS would cause the engine to quit completely. Resistances this low must decrease the voltage generated by the CAS to a value too low for the controller to use. The engine would not start with 200 ohm across one CAS and 1K ohm across the other. It didn't
matter which CAS had the lower resistance. The engine would start with 300 ohm across one CAS and 1K ohm across the other. This makes sense since the CAS cannot generate a very strong signal at cranking speed.
What doesn't make sense to me:
Starting with 1K resistance across each CAS, if the resistance on one CAS was increased to 69K, the engine would still run fine at 1500 RPM. If the resistance was
increased to 69K on the other CAS, the engine would only run on one rotor. It didn't matter which CAS resistance was increased first.
With 1K resistance across one CAS, changing the resistance of the other CAS from 69K back to 1K by connecting a wire would sometimes cause the engine would miss
what seemed to be one firing event. Again, there was no difference in the behavior of either CAS in this regard.
The conclusion seems to be that adding the 1K resistor to each CAS seems to be beneficial and the value of 1K is not critical or on the threshold of causing other
problems.
Steve
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