servo dynamo effect/reverse voltage
 

Ran across a thread on another forum discussing servo dynamo effect, and the OP in that thread seems to think that a quick movement of an control surface created a reverse voltage spike...hence taking out his ECU. I see Emcotec makes a device to combat this phenomenon in the form of the DPSI OCP http://shop.rc-electronic.com/downlo...yer_OCP_EN.pdf

Curious about this, so I had a go at a little testing using an Hitec 5955 servo. Quick/rapid movements of the servo arm produced voltage readings approaching 1.9v or 1.18 amps . Wondering if this backfeed would take out an ECU or receiver.

RE: servo dynamo effect/reverse voltage
 

Are you pushing the servo? Also... there is a small ESC in the servo, so I'm not sure how the voltage would be coming back, since the transistors would be "open" when not in use.

Also... I seriously doubt 1.9v would cause any damage since the servo is connected to the Rx, and the feed voltage is 4.8v or higher.

Personally, the guys saying his ESC was damaged from servo back-feed is just reaching for straws.


Lastly... if the "Dynamo Effect" was a real issue... we would all know about it, since servo's aren't a new development in the RC word. :D

RE: servo dynamo effect/reverse voltage
 

According to some radio manufacturers the dynamo effect does exist but is only a potential problem under certain circumstances and the device you linked to at Emcotec is not the right one. Multiplex says it can only be a problem with certain high power servos when the battery is blocked from absorbing voltage spikes by diode battery backers

http://www.multiplex-rc.de/en/produc...5c757e9973c3bf

http://shop.rc-electronic.com/e-vend...&t=6&c=67&p=67

RE: servo dynamo effect/reverse voltage
 

one of my 40% planes exhibited this, when forceably moving one control surface one or more of the others would move towards an end of there travel. I would not be to concrened about it and find it highly unlikely that it did any damage to the ecu.

Kevin