Will.iam Posted January 26, 2022 Report Posted January 26, 2022 How does the high low voltage warning light function? I ask this because today when i did my run up i always check each alternator separately and the second alternator on the belt turns faster at idle thus it outputs a charging current at idle but the engine mounted 1 alternator will not put out a charge until 1500 rpm or so. I verify this on my jpi battery voltage page when both are off 25v when #2 27-28v when #1 25v until i get the rpm above 1500 then it shows 27-28v. Well today my low high voltage light came on when #2 alt was the only one on even though my jpi showed 28v. Also strangely enough if i went to idle and turned on #1 alt even though it did not show higher than 25v the high low voltage light was still off. so recap: alt 1&2 - off voltage light on. Batt 25v alt 1&2 -on. Voltage light off. Batt 28v alt 1 on alt 2 off voltage light OFF batt 25v - 28v depending on rpm alt 1 off alt 2 on voltage light ON batt 28v all rpm speeds. so what does the high low voltage light run off of as it’s not just voltage since it does not come on when alt 1 is energized but my voltage reading is only 25v at idle. Quote
PT20J Posted January 26, 2022 Report Posted January 26, 2022 4 hours ago, rgpilot said: I believe the light flashes when voltage is too high and on steady when voltage is too low. Other way around Quote
PT20J Posted January 26, 2022 Report Posted January 26, 2022 22 hours ago, Will.iam said: How does the high low voltage warning light function? I ask this because today when i did my run up i always check each alternator separately and the second alternator on the belt turns faster at idle thus it outputs a charging current at idle but the engine mounted 1 alternator will not put out a charge until 1500 rpm or so. I verify this on my jpi battery voltage page when both are off 25v when #2 27-28v when #1 25v until i get the rpm above 1500 then it shows 27-28v. Well today my low high voltage light came on when #2 alt was the only one on even though my jpi showed 28v. Also strangely enough if i went to idle and turned on #1 alt even though it did not show higher than 25v the high low voltage light was still off. so recap: alt 1&2 - off voltage light on. Batt 25v alt 1&2 -on. Voltage light off. Batt 28v alt 1 on alt 2 off voltage light OFF batt 25v - 28v depending on rpm alt 1 off alt 2 on voltage light ON batt 28v all rpm speeds. so what does the high low voltage light run off of as it’s not just voltage since it does not come on when alt 1 is energized but my voltage reading is only 25v at idle. From your description, it appears that it is connected to the alt 1 output. I assume that by on you mean flashing (i.e., low voltage). Skip Quote
carusoam Posted January 27, 2022 Report Posted January 27, 2022 Each annunciator panel has various circuits to handle each output… How it handles a two battery / two alternator system must be interesting… See if your POH has a decent description of that part of the annunciator… What is meant by tripped a voltage relay? (In Skip’s POH page above) Check all the CBs and see what tripped? Reset only once… PP guessing only… -a- Quote
Will.iam Posted January 29, 2022 Author Report Posted January 29, 2022 On 1/26/2022 at 10:39 AM, PT20J said: From your description, it appears that it is connected to the alt 1 output. I assume that by on you mean flashing (i.e., low voltage). Skip Does not flash only comes on steady and only comes on steady when both alt off or alt 1 off with alt 2 on. I never get a flashing light. So if indeed on steady was over voltage then with both off and jpi battery meter dropping to 25v does not make since nor would having the light on with alt 2 showing 28v on jpi if the steady light meant over voltage how woukd turning on alt 1 make the light go out since the joi still shows 28v when adding alt 1 to the system. Now if the steady light is for low volts then why does it come on with alt 2 only and the jpi showing 28v but light goes out when on alt 1 only and jpi is showing 25v at idle or up to 28v if i rev up the engibe to 1500rpm? Quote
Will.iam Posted January 29, 2022 Author Report Posted January 29, 2022 On 1/26/2022 at 7:40 PM, carusoam said: Each annunciator panel has various circuits to handle each output… How it handles a two battery / two alternator system must be interesting… See if your POH has a decent description of that part of the annunciator… What is meant by tripped a voltage relay? (In Skip’s POH page above) Check all the CBs and see what tripped? Reset only once… PP guessing only… -a- No circuit breakers popped on the right panel. Anyplace else there would be a circuit breaker? Quote
PT20J Posted January 29, 2022 Report Posted January 29, 2022 8 hours ago, Will.iam said: Does not flash only comes on steady and only comes on steady when both alt off or alt 1 off with alt 2 on. I never get a flashing light. So if indeed on steady was over voltage then with both off and jpi battery meter dropping to 25v does not make since nor would having the light on with alt 2 showing 28v on jpi if the steady light meant over voltage how woukd turning on alt 1 make the light go out since the joi still shows 28v when adding alt 1 to the system. Now if the steady light is for low volts then why does it come on with alt 2 only and the jpi showing 28v but light goes out when on alt 1 only and jpi is showing 25v at idle or up to 28v if i rev up the engibe to 1500rpm? I don't have the manuals for your airplane. I was merely pointing out that the common condition is that the light is on whenever alt 1 is off. I would check the POH and confirm the operation of the light and look in the Service and Maintenance Manual for any troubleshooting information. Since this appears to be a new condition and the JPI indicates that both alternators are working correctly, it may be a problem in the annunciator circuitry. I think Paul @kortopates has dual alternators -- perhaps he has some ideas. Skip 1 Quote
carusoam Posted January 30, 2022 Report Posted January 30, 2022 22 hours ago, Will.iam said: No circuit breakers popped on the right panel. Anyplace else there would be a circuit breaker? Interesting question…. Some long bodies have a few CBs in the tail next to the batteries… I have only see pics around here… and don’t recall how many were back there and what was connected to them… Best regards, -a- Quote
kortopates Posted January 31, 2022 Report Posted January 31, 2022 If bus voltage is 28V and your getting a high voltage annunciation (solid red light), that suggest an annunciator issue. I would first review the troubleshooting steps on the annuciator in the service manual and also verify the large pin connector to the annunciator at its rear is still solidly attached since there is no hardware that secures it - it's just pushed on and can become loose. Then I'd check with the OEM of the annunciator in Texas. He may have additional thoughts before returning it to him. But he services them and is not expensive. On the #1 alternator, are you sure it doesn't come in till 1500 rpm? It's coming in speed should be in the 1100-1200 rpm, not coming in till 1500 rpm would have me pulling it expecting to replace worn brushes. Our alternators are very serviceable, no need to go buy a new/OH exchange alternator. 1 1 Quote
Will.iam Posted January 31, 2022 Author Report Posted January 31, 2022 5 hours ago, kortopates said: If bus voltage is 28V and your getting a high voltage annunciation (solid red light), that suggest an annunciator issue. I would first review the troubleshooting steps on the annuciator in the service manual and also verify the large pin connector to the annunciator at its rear is still solidly attached since there is no hardware that secures it - it's just pushed on and can become loose. Then I'd check with the OEM of the annunciator in Texas. He may have additional thoughts before returning it to him. But he services them and is not expensive. On the #1 alternator, are you sure it doesn't come in till 1500 rpm? It's coming in speed should be in the 1100-1200 rpm, not coming in till 1500 rpm would have me pulling it expecting to replace worn brushes. Our alternators are very serviceable, no need to go buy a new/OH exchange alternator. I think you nailed it with the pin connector in the back as i had the top panel off the other day checking my connectors as my Radio Alt needle is bouncing between 100 to 300 ft and i wanted to make sure the connection at the connector was not the issue. I bet $20 i bumped that connector on the test panel off or loose. Will have to go double check those connections tomorrow. Thanks for the info! 1 Quote
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