Home
What's new
Latest activity
Authors
Store
Latest reviews
Search products
Forums
New posts
Search forums
What's new
New posts
New listings
New products
New profile posts
Latest activity
Members
Current visitors
New profile posts
Search profile posts
Log in
Register
Cart
Cart
Loading…
What's new
Search
Search
Search titles only
By:
New posts
Search forums
Search titles only
By:
Menu
Log in
Register
Navigation
Install the app
Install
More options
Change style
Contact us
Close Menu
Forums
Cobra Forums
The Terminator
Terminator Talk
Cluster inverter reverse engineering project
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="mwolson" data-source="post: 16988716" data-attributes="member: 16006"><p>Time for an update. I have actually been doing a lot of work on this project in spite of not having any more failed inverters to analyze. To recap, I have been able to diagnose 3 bad clusters. Two had bad EL panels and one had a blown inverter.</p><p></p><p>It is easy to diagnose a bad panel. If you disconnect the inverter from the panel and put an ohmmeter across the panel pins, you should see a really high resistance and see it go up until it is off the scale if the panel is good. If the resistance is lower and is a fixed resistance, the panel is bad. The two failed panels I saw were in the 10s of K ohms. There is no way to fix a blown EL panel that I know of.</p><p></p><p>The one bad inverter I have has a blown (open circuit) primary winding. There are no off-the-shelf transformers that I have found that will work in this circuit. We will need to have custom transformers made if we want to replace blown transformers. I had expected that the transistor would be the culprit, but not in this one case.</p><p></p><p>The transistor that Ford used is a cheap Chinese transistor made by a company called Zetex. There are no specs available for that transistor, but the curve traces I made from the one in the failed inverter shows that it is pretty much a standard NPN small signal transistor.</p><p></p><p>I measured the transformer to figure out the spec as best that I could. I got good inductance measurements for the secondary winding and the feedback winding from the bad transformer. I didn't want to risk the one working loaner inverter that I have so I didn't take the good transformer out of the circuit on that one to read the primary winding. I measured it in the circuit, and I hope that it is close enough.</p><p></p><p>I put the entire circuit into the LTSPICE simulator and got it to work. I tried a bunch of different small signal NPN transistors and they all worked. This implies that just about any small signal NPN transistor with the correct pinout will probably work in the circuit, just need to check the voltage and current specs to make sure that the max values aren't exceeded.</p><p></p><p>The transformer inductances I measured also worked in the simulation which implies that we could get custom transformers made using those specs to replace any blown transformers.</p><p></p><p>It is also possible to design a new inverter circuit to replace the entire inverter. I am also looking into that, which could use a cheaper, currently available off-the-shelf transformer.</p><p></p><p>While looking into all of this, I learned that EL panels are pretty much like a capacitor that emits light whenever the cap is being charged. The higher the voltage and/or the higher the frequency, the brighter the EL panel will be. However, the higher the voltage and the higher the frequency is, the shorter the life of the panel will be.</p><p></p><p>The SpeedHut inverter puts out a lower peak-to-peak voltage than the OEM inverter does, which is why I assume that the panels are dimer when using the SpeedHut inverter compared to using the OEM inverter. However, the SpeedHut inverter works at about 1.5KHz vs the OEM inverter that works at about 500Hz. I don't know if voltage or frequency has more impact on EL panel longevity. It is possible that the SpeedHut inverters will lead to a longer life for the EL panels or a shorter life.</p><p></p><p>If I wind up designing a replacement inverter for these vehicles, I will target 300V P-P and 500Hz to keep it as close to the OEM inverter as possible.</p><p></p><p>I am not interested in making a big investment in either replacement transformers or a new inverter if there aren't many failures. To date, I have only seen 3 failed systems.</p><p></p><p>I will keep playing with the new inverter circuit from time to time, but this project will not be on the front burner until I see at least a few more failed inverters.</p></blockquote><p></p>
[QUOTE="mwolson, post: 16988716, member: 16006"] Time for an update. I have actually been doing a lot of work on this project in spite of not having any more failed inverters to analyze. To recap, I have been able to diagnose 3 bad clusters. Two had bad EL panels and one had a blown inverter. It is easy to diagnose a bad panel. If you disconnect the inverter from the panel and put an ohmmeter across the panel pins, you should see a really high resistance and see it go up until it is off the scale if the panel is good. If the resistance is lower and is a fixed resistance, the panel is bad. The two failed panels I saw were in the 10s of K ohms. There is no way to fix a blown EL panel that I know of. The one bad inverter I have has a blown (open circuit) primary winding. There are no off-the-shelf transformers that I have found that will work in this circuit. We will need to have custom transformers made if we want to replace blown transformers. I had expected that the transistor would be the culprit, but not in this one case. The transistor that Ford used is a cheap Chinese transistor made by a company called Zetex. There are no specs available for that transistor, but the curve traces I made from the one in the failed inverter shows that it is pretty much a standard NPN small signal transistor. I measured the transformer to figure out the spec as best that I could. I got good inductance measurements for the secondary winding and the feedback winding from the bad transformer. I didn't want to risk the one working loaner inverter that I have so I didn't take the good transformer out of the circuit on that one to read the primary winding. I measured it in the circuit, and I hope that it is close enough. I put the entire circuit into the LTSPICE simulator and got it to work. I tried a bunch of different small signal NPN transistors and they all worked. This implies that just about any small signal NPN transistor with the correct pinout will probably work in the circuit, just need to check the voltage and current specs to make sure that the max values aren't exceeded. The transformer inductances I measured also worked in the simulation which implies that we could get custom transformers made using those specs to replace any blown transformers. It is also possible to design a new inverter circuit to replace the entire inverter. I am also looking into that, which could use a cheaper, currently available off-the-shelf transformer. While looking into all of this, I learned that EL panels are pretty much like a capacitor that emits light whenever the cap is being charged. The higher the voltage and/or the higher the frequency, the brighter the EL panel will be. However, the higher the voltage and the higher the frequency is, the shorter the life of the panel will be. The SpeedHut inverter puts out a lower peak-to-peak voltage than the OEM inverter does, which is why I assume that the panels are dimer when using the SpeedHut inverter compared to using the OEM inverter. However, the SpeedHut inverter works at about 1.5KHz vs the OEM inverter that works at about 500Hz. I don't know if voltage or frequency has more impact on EL panel longevity. It is possible that the SpeedHut inverters will lead to a longer life for the EL panels or a shorter life. If I wind up designing a replacement inverter for these vehicles, I will target 300V P-P and 500Hz to keep it as close to the OEM inverter as possible. I am not interested in making a big investment in either replacement transformers or a new inverter if there aren't many failures. To date, I have only seen 3 failed systems. I will keep playing with the new inverter circuit from time to time, but this project will not be on the front burner until I see at least a few more failed inverters. [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Cobra Forums
The Terminator
Terminator Talk
Cluster inverter reverse engineering project
Top