Jasco alternator upgrade

[krines]

I am considering the upgrade but in my reading on previous topics concerning this there was mention that the piano key switches could not handle the increase in power. I dont want to loose the piano keys. Comments? Steve

[KS170A]

Steve,
I do not see why you would have to do away with the "piano switches." Power comes from the alternator/generator and first comes to the hot side of the fuses/circuit breakers. Those fuses/CB's are rated to protect the wiring, and also the switches and equipment (but officially, they're to protect the wires). Being as how the switches are on the protected side, and assuming no changes are made downstream of the fuses/CB's, you should be able to go on as you have.

I took a couple pictures when I had my switch panel out. It consists of standard AN switches whose toggles protrude into grommets in holes on the piano keys. If it is necessary to change the switches for some reason, you "simply" replace the switch itself, keeping the piano. I put simply in quotes because anyone who's done it knows it can be a real pain to replace just one.

[DWood]

I have had a Jasco on my 48 for many years. I am not aware of any modification with the Piano switches. You will need to increase the wire size to the buss to handle the potential increase in current and to add the 50 AMP Breaker. That might be what you heard. You can go to the Skytronics Jasco website to see the wiring diagram.

http://www.skytronicsinc.com/jasco_wiring-diagrams.html

[krines]

Great that clears it up for me and makes sense to what I had seen on the wiring diagram. I saw a comment about the switches in previous discussions and it had me wondering if I was missing something. I wil procede. Thanks guys. Steve

[n2582d]

Steve,
According to the TCDS the C-145-2 engine is required to have a dampened crankshaft if it has a 35 amp. generator. In spite of the parts catalog indicating that the only undampened crankshaft was for the C-125 engine, apparently there were some early C-145 crankshafts that were undampened. I'd be reluctant to add an alternator with 35 amps or greater to an engine with an undampened crankshaft. There's a 99% chance that your crank is dampened but it's worth checking. See this discussion.

[krines]

I was aware of the dampened crank issue and I have just rebuilt my engine and have seen directly that it is dampened. Thanks for lookin out for me though. Steve

[anjlena1]

Moderators note: While this info borders heavily toward disallowed advertising and has nothing really to do with the installation of a Jasco on a 170 which is what the thread is about. We will let it stand because it is nice to know info for Jasco owners and it very well might be nice to know BEFORE you are a Jasco owner.

• Skytronics, Inc. is the name to trust when your Jasco Alternator needs overhaul. Because we are the manufacturer of the Jasco line, our overhaul shop technicians are trained to rebuild your alternator and regulator to factory new specifications, and use only FAA/PMA original replacement parts. Upon completion, our overhaul service also gives you confidence in knowing that your rebuilt alternator and regulator now carries the same factory warranty that it carried when it was new.
  
  When selecting an overhaul shop for your alternator system, there are a couple of things to keep in mind about others who claim they can service your Jasco Alternator or Regulator.
  
  Skytronics, Inc. is the only repair station authorized by the FAA to overhaul the Jasco product line.
  Without Jasco PMA parts on the inside of your Jasco Alternator and Regulator, the FAA/PMA approval on the outside is void along with any STC or FAA Form 337 installation approvals.
  The Jasco warranty is void, once the cover is removed from the Alternator or Regulator by other than Skytronics' engineers.

[blueldr]

If you have a requirement for more amps than one of the piano key switches can handle, simply install a small relay for that circuit.

[GAHorn]

(I suggest folks generally disregard the blatant unauthorized advertisement just posted.)

Steve.... sorry to not have offered a suggestion previously in response to your original question....(and it's unfortunate that the "only authorized Jasco" person didn't have the smarts or the spirit to supply the correct answer).... but, the correct answer is likely that the Jasco installation instructions haven't a clue as to the capacity of your previous generator installation...nor the capacity (ampacity) of the cockpit switch controlling it.

The previous generator was likely either a 12, 20, 25, or 35 Amp unit. Presumeably the wires from the generator Armature to the regulator/buss and control switch was of sufficient gauge to accomodate that units' capacity....and presumeably the switch controlling that circuit was also of an appropriate capacity.

If your Jasco unit is the typical 50 Amp unit, then the wiring from the alternator to the aircraft systems AND THE SWITCH must be of a capacity/size/gauge suitable to handle the load, and for that reason they merely tell you to change all that out accordingly.

Chances are the switch installed was a 30A switch (but you'd have to confirm that by actual part number. Most of them are common AN switches with the PN imprinted upon the case, but age and lousy record-keeping....(was yours ever changed-out previously???)... probably require you to either get under the panel to inspect it (something you should do when you replace the wiring anyway) and/or simply plan to obtain an appropriately-sized/rated switch and replace it, using the pictures and suggestions already supplied in this thread.

Hope that helps explain it. Chances are you used the existing switch already and have not yet demanded a full 50 Amps from your new alternator and therefore have not over-stressed/burned-up your switch.... but beware of the possibilities.

Hope that helps. (And by the way, any good alternator shop can probably service your Jasco and the bearings are available at any good bearing supply.)

[krines]

Thanks George, You are absolutely correct about the switching and wiring. You may notice that my original topic is dated and I have actually completed the transition. Our trusty Jasco rep must have been searching the web and added the last reply. Electronics have always befuddled me so I enlisted the help of the local aircraft electrician and we updated the wiring. He was somewhat shocked at its condition and would have grounded the plane if he inspected it. All is working well. I dont know if is just all the money I spent but it seems the engine runs smoother with the new alternator. That does not make logical sense however. Thanks Steve

[48RagwingPilot]

Looking at the picture of the piano key switches, can anyone tell me what the non-switch device is in the middle of the assembly? Thx.

[krines]

Decoration

[48RagwingPilot]

Seriously, I would like to know.

[blueldr]

With the use of modern electronics and associated parts in our communications equipment, there remains a doubt in my mind on whether or not we really need more 12 volt amperage than would be available with even the smaller cacacity generators.
What after-market, or other than original C-170 equipment, would require a heavy amperage load ?

[n2582d]

Looking at the picture of the piano key switches, can anyone tell me what the non-switch device is in the middle of the assembly? Thx.

Klixon circuit breaker