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OV protection

sahrens

sahrens

Well Known Member
As I flew home yesterday, I watched my volts slowly start dropping. Only one possibility, my PlanePower alternator is / was failing. It might be the regulator but as a combined unit it doesn’t really matter. This is the second PlanePower in 300 hours, time for something different.

I’ve researched and read posts on using a Honda Civic or Suzuki Samari alternator (30 amp) with a Ford LTD regulator. What I have found is an OV protection device. B and C doesn’t sell a stand alone OV module. They do sell a regulator with OV protect for $325.00. Looking for a stand alone option.

Any suggestions?

Thanks
 
See if it is available from this source in France, same device as originally available from B&C.
https://aero3d.fr/fr/accueil/3339-ovm-bc-over-voltage-protection-module-ovm-14.html

ovm-bc-over-voltage-protection-module-ovm-14.jpg


B&C has this device in their installation kit for permanent magnet backup alternators, you might see if you can talk them out of one. :)

https://bandc.com/product/pm-ov-filter-and-ov-protection-kit-14v-2/

PMOV_Kit-300x300.jpg


If you are an electronic junkie and want to build an OV device, here is a schematic:

http://www.aeroelectric.com/DIY/DIY_Crowbar_OVP_F.pdf
 
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No joy

Sadly the French connection only ships to the EU. I looked at the BandC overvoltage kit but its only rated to 15 AMPs. I am not that much of an electrical junky just tired of giving my money to PlanePower.

But thank you very much for sending me some options. I appreciate it.

Scott
 
Simplest DIY

But you'll probably have to get the MBS4991 from eBay as it's "obsolete".
S4025, S6025, S4030 or equivalent SCRs will all work. 40, 60 is voltage. 25, 30 is amps. 40 volts or higher will all work and 25 amps or higher will all work. But their trigger voltages may be somewhat different and may require changes to the 5.49K and 4.75K resistors if the adjustment range will not get you to your desired activation voltage. (I use 16 to 16.5V.)

Notice that the wire gauge and length from the circuit to the breaker is important. Too short or too thick a wire and you'll fry the SCR before the breaker pops. I would recommend at least a foot or two of 20AWG or 22AWG.

Attached picture of too short and thick wires (had it mounted on the Alternator breaker.)

Note: you don't need to mount the components on a circuit board. It's possible to just solder the components together.

Finn
 

Attachments

  • overvoltage module with B-lead relay CbOV-14_Installation_A.pdf
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  • OV.jpg
    OV.jpg
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BillL said:
I see it says OVP, but is that to protect attached load or itself? The spec sheet I found had no voltage trigger for the OVP listed.
Click to expand...

OVP in an 12V system external VR meaning anything but monitoring the DC voltage coming from an external power source and protecting the rest of the connected circuitry using one of two methods: a crowbar clamp circuit or a series-connected switch, would be false advertizing. The V1700 at $150 may be a better footprint. The adjustable output voltage and OVP made it a no brainer for me.

I emailed WAI Transpo, but I'm guessing it is a switch, not a crowbar. No guarentee of fuse or circuit breaker in a non-aviation product's sense circuit.

I bet it is similar to a Zeftronics $450 unit-

"The Zeftronics R15V00 ACU (alternator Control Unit) is a direct replacement for OEM ACU units but requires the removal of the Cessna Over Voltage Sense unit PN C593001-0101 located between the Alternator Switch and the Alternator Field Circuit breaker. The Over Voltage Sense Unit will need to be removed from the circuit and just the Noise Suppressor left in the circuit."

"The R15V00 Rev A is a 14Vdc electronic Alternator Controller (Voltage Regulator and Over Voltage Sensor) designed for use with 12Vdc aircraft alternators. It combines the OV Sensor and regulator in one unit that is fully pin and function compatible with the Cessna equivalent units. This unit provides Voltage Regulation, Overvoltage Protection, Low/High Voltage indicator pin, self-protecting Field-to-ground short protection, as well as an on-unit Trouble-Shooting Light (TSL). The OV sensor removes power from the regulator thus dropping the alternator off-line when the sysytem voltage exceeds 16 volts. The indicator pins allows a light connected to it and bus to come on whenever the alternator switch is open, the OV sensor is defective (open), or the wire to pin S is open. The unit will turn itself off and turn on a RED TSL light if it senses that the alternator field or field wire is shorted to ground. When the ground fault is removed or repaired, the unit with come back on line (with a GREEN TSL light) once the alternator switch is cycled. If the wire from the alternator battery terminal to pin A is broken, the on-unit light will be OFF."
 
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