Topic: Suspect pod fault

[Pep]

Hi guys, does anyone know what the pod is thinking;

Full battery leds - with charged battery, and the end yellow leds are lit for both power and load side displays
When I press power the motor runs, the battery power and yellow leds remain lit, the single innermost red led lights, C5 on tressles and no driving load

I have replaced Tr1, Tr2, D1, D3 & D4 in the CB
The pod had a broken track at R2 now fixed

The thermister valve in a unheated garage connected to X6 pin 1,2 grey and purple wire 11.2k ohm, is this value ok
When using a variable resistor for the thermister slightly above 1k ohm no leds but beeping at 1 Hz, below 1k ohm all the load leds flash approx 1Hz no beeping

If I swap a variable bench power supply for the battery the power leds do not drop out one by one as I reduce the voltage, and all drop out at around 5.5v

Would I be right in thinking that the CB is fine and is the fault is with the pod or ULA chip

I am planning to join the 24v club soon, so wouldn't need these then, but I would like to have them working if possible, if I am frightened by the extra speed I may want to change back !

I have fitted a 75mm fan to the rear of the motor with all of the air passing through the inner core of the motor via a shroud, I have seen larger fans with air passing over the outer surface as well, would this give enough cooling carrying a 15 stone ripped male ??
We were running our C5 most of the day at Brooklands without temp control and cooked the motor, I think the magnets have moved, and the rotor binds on them, is there any way to repair this, if so I will keep this for a spare

Sorry to load all the questions at once but the good news is that my headlight arrived today and replaces the previous shattered unit, it looks like a real C5 now !!

Thanks 

[KarlG]

From your description it looks like an incorrect battery connection at some time or other.

I have replaced Tr1, Tr2, D1, D3 & D4 in the CB

Have you also checked the ICs in the CB?

If it the problem was caused by an incorrect connection then the POD semiconductors are almost certainly affected.

Do you intend to retain the POD for future use?  If yes then I would recommend that you contact Chas, he informed me that there is a service to check these items. Should the ULA chip be damaged then it's going to be a big problem, they are now as rare as hen's teeth.

Just a tip, Phil has a solution for damaged ULAs. Look here: http://cypax.net/projects/ula/index.php?language=en

Of course if you are going to convert then all this info is irrelevant, just throw the POD case in my direction. 

[KarlG]

Concerning the fan.

Most of the heat produced in the C5 motor is produced by the armature. Therefore, this being internal, it is more important that the air is passed through the motor than around it.

The inlet apertures at the fan end are more numerous and larger than those at the other end.

1. The armature and magnets should be kept as cool as possible.

2. Air always takes the path of least resistance so if you fit an over-sized tube and fan most of the air will pass over the casing and not through the motor.

3. Air passing through the motor will also cool the casing, but air passing over the casing will not cool the armature.

4. If no filter or gauze is fitted to the fan intake there is the possibility that small particles, e.g. paper, leaves etc., can be sucked into the motor, pass through the inlet apertures only to be caught in the outlet. This leads to overheating, and the motor will/should shut down.

EDIT: One thing to check before obtaining a fan, taking a given size some fans can move up to three times the cubic air capacity than some of the others.

[radiomarty]

Hi Pep - as Karl says there is an ic in the control box that can cause this fault ie the op amp however if this is the same pod you had at Brooklands then I think we checked it on a known good control box so the fault is in the pod. You are welcome to post it to me and I can check the ula free of charge -Marty

[KarlG]

Hi Pep,

thank goodness you mentioned the thermistor. I went to check the value for you only to find it's MISSING. 

@ Marty,

Hi Marty, do you have the value of the original C5 thermistor?

Cheers.  KarlG.

[radiomarty]

Hi Karl  - the make is Microtherm type T11 - Data sheet can be downloaded here :

http://www.datasheetarchive.com/microtherm%20t11-datasheet.html

[KarlG]

Hi Marty,

thanks for the info, but Microtherm type T11 is the thermal cutout.  Any idea who produces the thermistor?

[radiomarty]

Hi Karl - not 100% sure of the original manufacture of the thermistor - I did read somewhere it was an NTC 10k but never having to have replaced one im not !00% on that -I will endeavor to find out - similar post
http://c5alive.co.uk/forum/index.php?topic=1205.0

[Pep]

Hi Karl G, I have only checked IC1 for 12v and 5v which is ok,
I hope you find your thermister, perhaps Retro Andy could help you look for it with his super x-ray 40x40 vision after finding his boot clip.

I would like to use the pod with the 24v system as that will keep the original C5 appearance,

Marty the pod is the same one we tried at Brooklands, you suggested replacing R2 which was ok,  I would like to take you up and send it on to you now for repair if possible,

Thanks Guys 

[KarlG]

Well I don't think there is any chance of finding the termistor as, if what I read is correct, it's made of glass.

The thermistor orifice in the armature has a finite depth of 41mm (at least the one I have). The butchers that castrated the CB and other parts of the electrics have pushed the thermistor too far down the mounting tube, net result is the thermistor has been  ripped off. 

At least I have one on #1 that I can use for the meantime.

[radiomarty]

Hi Pep - email sent - Marty