Fan Stuff Again...Amplifier Issue And Temporary Remedy
06-25-2014, 10:10 AM
#16
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Not sure where you are getting 19.2 volts. Battery voltage should not exceed 13.6 volts. If you are really getting 19.2 volts, there is a voltage regulator issue that is the root cause of your problems and the final stage will fry again.
Follow up on this as it is not correct. If you really have 19.2 volts to the fan, there is a problem.
Follow up on this as it is not correct. If you really have 19.2 volts to the fan, there is a problem.
06-25-2014, 10:53 AM
#17
Nordschleife Master
Thread Starter
Not sure where you are getting 19.2 volts. Battery voltage should not exceed 13.6 volts. If you are really getting 19.2 volts, there is a voltage regulator issue that is the root cause of your problems and the final stage will fry again.
Follow up on this as it is not correct. If you really have 19.2 volts to the fan, there is a problem.
Follow up on this as it is not correct. If you really have 19.2 volts to the fan, there is a problem.
Add: Checked them twice with same result.
06-25-2014, 11:36 AM
#18
Nordschleife Master
Thread Starter
Guys would the following be an at risk issue for the my car's electrical system ?
My final output amplifier has failed. Only one fan functions. My above testing per the WSM I believe shows this failure to be the case. I had been driving the car for a week with one fan while waiting for my new one to arrive - never got 'hot' except for one time when I purposely made it do so by remaining stationary for a reason. I live in rural Northern Maine - the climate and traffic patterns are not problematic, and my car is exceptionally tuned in all systems.
I was thinking about this until I get a rebuilt amplifier unit.
Disconnecting the fan harnesses and running them off of a direct fused power line through a two stage/speed switch. My one fan now is receiving 19.2v with the engine running - that won't work for me. I have a convenient place in mind for the switch. Actually, I will rarely use it up here. I will do this for a brief period until I have the funding for the amplifier - I have had a recent calamity in my life which has thunderstormed on my parade - will be behind me shortly.
Does anyone see system issues in doing this ?
Please let me know. I don't want to run on one fan with a 19v feed for long.
Thanks
My final output amplifier has failed. Only one fan functions. My above testing per the WSM I believe shows this failure to be the case. I had been driving the car for a week with one fan while waiting for my new one to arrive - never got 'hot' except for one time when I purposely made it do so by remaining stationary for a reason. I live in rural Northern Maine - the climate and traffic patterns are not problematic, and my car is exceptionally tuned in all systems.
I was thinking about this until I get a rebuilt amplifier unit.
Disconnecting the fan harnesses and running them off of a direct fused power line through a two stage/speed switch. My one fan now is receiving 19.2v with the engine running - that won't work for me. I have a convenient place in mind for the switch. Actually, I will rarely use it up here. I will do this for a brief period until I have the funding for the amplifier - I have had a recent calamity in my life which has thunderstormed on my parade - will be behind me shortly.
Does anyone see system issues in doing this ?
Please let me know. I don't want to run on one fan with a 19v feed for long.
Thanks
Gurus...?
06-25-2014, 11:53 AM
#20
Nordschleife Master
Thread Starter
I thought too that those voltages were unfathomable.
How I first noted the new fan didn't function was when I pulled into driveway was was talking to son while idling warm. The fan went on on both my son and I stopped in wonder - the fan sounded like a Cessna like I've never heard it before even when I was on the one same fan due to the other fan mechanical failure.
I wasn't sure if the amplifier 'amplified' through some capacitator or other 'magical' function.
Alan,
What are your thoughts on the temporary bypass ?
06-25-2014, 11:59 AM
#21
Rennlist Member
I have a couple of spares - you are welcome to use one until you have the funds to either replace it new or buy the used one.
06-25-2014, 12:12 PM
#22
Nordschleife Master
Thread Starter
Thanks. I may take you up on a functional used one. I think upgrading the FET's would be helpful on an already functional unit.
Simos Quote:
"Don't remember exactly the aperage of original FET, but it was something like 25 - 30A. The fuse is 30A and therefore the FET may blow first.
I replaced the original with 50A FET and no issues anymore. However, it's important to check first that both fans are spinning freely without any bearing etc. issues.
There are also 70A FETs with same housing size, but first thing is to check that you use correct fuse size and fans are spinning freely.
It's the fuse which should secure the electrical circuit, not any other component. Also the higher amperage FET may stay cooler while operating.
I think, it's the fan starting current which blows the FET as it can be several times higher than nominal current.
Don't trying to engourage anyone to doing same thing, but this is how I see the issue with cooling fan final stage."
Captain Slow Quote :
"Simos....great observation. The original BUZ11A MOSFETs are 50V 26A .045 Ohm Some of the new equivalent replacements are 30A"
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06-25-2014, 12:16 PM
#23
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Craig:
Any chance that you are dealing with a mechanical problem rather than an electrical one. Original fan craps out. Replace with a new unit. New unit craps out.
As I've mentioned numerous times, I hate chasing electrons but is there any chance that your fan motor casing gets slightly distorted on installation thereby causing the bearings/bushings to slightly misalign enough to prevent starting. Just a thought.
Barney
Any chance that you are dealing with a mechanical problem rather than an electrical one. Original fan craps out. Replace with a new unit. New unit craps out.
As I've mentioned numerous times, I hate chasing electrons but is there any chance that your fan motor casing gets slightly distorted on installation thereby causing the bearings/bushings to slightly misalign enough to prevent starting. Just a thought.
Barney
06-25-2014, 12:21 PM
#24
Nordschleife Master
Thread Starter
Craig:
Any chance that you are dealing with a mechanical problem rather than an electrical one. Original fan craps out. Replace with a new unit. New unit craps out.
As I've mentioned numerous times, I hate chasing electrons but is there any chance that your fan motor casing gets slightly distorted on installation thereby causing the bearings/bushings to slightly misalign enough to prevent starting. Just a thought.
Barney
Any chance that you are dealing with a mechanical problem rather than an electrical one. Original fan craps out. Replace with a new unit. New unit craps out.
As I've mentioned numerous times, I hate chasing electrons but is there any chance that your fan motor casing gets slightly distorted on installation thereby causing the bearings/bushings to slightly misalign enough to prevent starting. Just a thought.
Barney
06-25-2014, 01:53 PM
#25
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Back to 19.2 volts, is this real? Not sure how you could get that number. I would check at the fan connection (will need long probes) with another meter. Borrow an analog meter from someone, calibrate with a known battery source, and compare readings. Need to resolve this first, as you are leading yourself down the wrong path. You may indeed have a bad voltage regulator that is spiking and it could destroy another final stage.
While it is tempting to bypass the system, I ran the entire SITM with one fan. Unless it is really hot outside, you should be OK.
Dave
While it is tempting to bypass the system, I ran the entire SITM with one fan. Unless it is really hot outside, you should be OK.
Dave
06-25-2014, 01:59 PM
#26
Former Sponsor
How about running a couple of Bosch Power relays to the fans and just use the signal from the fan controller to turn them on?
Or, even easier, just take Kevin up on his offer....very nice, Kevin!
Or, even easier, just take Kevin up on his offer....very nice, Kevin!
06-25-2014, 02:02 PM
#27
Former Sponsor
Regarding the "higher than 13 volts" fan voltage.
I thought that the final stage fan unit was an amplifier?
I thought that the final stage fan unit was an amplifier?
06-25-2014, 02:40 PM
#28
Nordschleife Master
Thread Starter
06-25-2014, 02:47 PM
#29
Drifting
"I thought that the final stage fan unit was an amplifier?"
Good point...most decent consumer grade stereos are using MOSFET controlled amps. There are some good sized capacitors in the final stage controller. I noticed my original final stage doesn't spin the right fan at all. Putting in a used final stage I saw the right fan try to start. Perhaps the capacitors failing can be another reason a fan won't turn. I'm guessing the capacitors deliver a higher voltage and current needed to start the fans??? Makes sense in terms of simple physics - it's like mashing the accelerator to get up to speed (over come inertia when fan is at rest), then nominal system voltage is enough to keep 'em spinning???
Good point...most decent consumer grade stereos are using MOSFET controlled amps. There are some good sized capacitors in the final stage controller. I noticed my original final stage doesn't spin the right fan at all. Putting in a used final stage I saw the right fan try to start. Perhaps the capacitors failing can be another reason a fan won't turn. I'm guessing the capacitors deliver a higher voltage and current needed to start the fans??? Makes sense in terms of simple physics - it's like mashing the accelerator to get up to speed (over come inertia when fan is at rest), then nominal system voltage is enough to keep 'em spinning???
06-25-2014, 03:08 PM
#30
Nordschleife Master
Thread Starter
"I thought that the final stage fan unit was an amplifier?"
Good point...most decent consumer grade stereos are using MOSFET controlled amps. There are some good sized capacitors in the final stage controller. I noticed my original final stage doesn't spin the right fan at all. Putting in a used final stage I saw the right fan try to start. Perhaps the capacitors failing can be another reason a fan won't turn. I'm guessing the capacitors deliver a higher voltage and current needed to start the fans??? Makes sense in terms of simple physics - it's like mashing the accelerator to get up to speed (over come inertia when fan is at rest), then nominal system voltage is enough to keep 'em spinning???
Good point...most decent consumer grade stereos are using MOSFET controlled amps. There are some good sized capacitors in the final stage controller. I noticed my original final stage doesn't spin the right fan at all. Putting in a used final stage I saw the right fan try to start. Perhaps the capacitors failing can be another reason a fan won't turn. I'm guessing the capacitors deliver a higher voltage and current needed to start the fans??? Makes sense in terms of simple physics - it's like mashing the accelerator to get up to speed (over come inertia when fan is at rest), then nominal system voltage is enough to keep 'em spinning???