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 Post subject: Reverse fitment -
 Post Posted: Fri Jul 01, 2016 6:36 am 
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Joined: Tue Nov 27, 2012 11:59 am
Posts: 384
Location: Sunshine Coast, Qld
IMPORTANT ANNOUNCEMENT REGARDING TRI POD REVERSE CIRCUITS -

A note to those who may have downloaded, been supplied with and in fact have used the reverse control circuit I have offered over the last couple of years (there has only ever been one version until now).

A number of improvements have been made to both the circuits (motor control and actuator control) and I no longer suggest the usage of either.

THE ISSUES ! PLEASE READ !

1) I never suggested a particular rating for either of the relays but have only ever supplied a very high quality US made item for the 24v circuit. This was supplied on the basis that really as much as the circuit offered a 12/24v low/high power option most users only ever use the 24 v setting as full torque is generally required for useful reversing of the vehicle. Primarily the 12v mode was designed in as a back up plan if the extra 24v setting battery went flat (as it is not automatically charged like the cars main battery). The 12v mode would still allow some reversing capability under this circumstance. The high quality 24v solenoid has had zero failures that I am aware of.

BUT the 12v relay often used by installers of the reverse system (standard 30A, 40A or higher rated 70A) can fail. The failure of this relay generally in my experience involves the contacts burning and 12volts no longer being fed to the motor. A somewhat inconsequential failure and one that with use of the 70A higher rated standard relay design rarely happened.

A FURTHER 'BUT' - Yesterday a relay in use by myself for controlling the 12v switching of the reverse motor failed internally though in a different way that I have never seen in 35 years of working professionally in electronics. The high current contacts became connected to the coil somehow through an internal breakdown and therefore even when the coil switching voltage was removed (unpressing the 'go' button for reverse operation) the contacts in the relay remained engaged and 12 volts remained fed to the reverse motor resulting in short term panic and longer term embarrassment. No harm was done, no animals or children were injured, the wires were quickly removed from said relay but it is a reminder that in this age of reduced quality standards perhaps items or faults regarded as impossible or so unlikely as to ever really happen may happen.

THE FIX - I suggest that for the moment the two speed 12/24v aspect of the reverse motor control circuit be disabled. All that be need done is disconnect the 12v relay main high current motor feed wires and either insulate and tie them up with a cable tie or similar or of course remove them all together. I would also disconnect the 12v coil switching voltage wire as well and insulate as appropriate. For those wanting to retain the low/high power option I have quickly drawn up a revised circuit with suggested part numbers for over engineered reliable operation and once drawn up in CAD will publish the circuit for all Tri Pod Cars reverse kit customers.

A FURTHER FIX - You might ask "but what if this happens in 24v mode?". Well in theory this almost should never happen due to the much higher quality relay/solenoid and the fact that it is purposely more highly rated but now having experienced the rather uncomfortable feeling of taking ones finger off the 'go' button but the 'go' keeps going I suggest some kind of isolation switch for the reverse motor. I will make a technical suggestion on this soon.

SO WHAT DO YOU THINK HAPPENED? In theory a 450W 24v motor draws less than 20A. Of course when stalled (or during the getting rolling stage of operation) it will draw dramatically more. I feel though a 100A high quality solenoid is adequately rated for the short term current draw that will exceed the calculated 20A. My own test vehicle (and Jesse's silver bandit version) has proven this to be the case over nearly 70,000kms worth of reversing time. BUT the 12v relay generally used and treated by myself as a bit of an after thought may well be underrated. 70A offers some headroom for an over current situation but I feel that rating in itself is less likely to be accurate or have any level of headroom or "under rating" due to its much lower cost and expected real world quality. A combination of lower quality and the likelihood that even when using a 24v motor at 12v and the expected output of power is halved the current draw may well be similar to 24v operation. Nonetheless I feel the failure I have experienced is unlikely to ever happen again and was largely brought on by a dodgy sample BUT I live and learn and have revised my suggested circuit accordingly.


2) In the actuator drive circuit I have used the neutral light actuation as an interlock so the vehicle has to be in neutral for the actuator to operate and lower. This is the way that it should be but variations in how the different donors (Bandit, Blackbird, ZX, Busa etc) drive their neutral light mean I need to re write the circuit to reflect these differences.

PLEASE DISREGARD THE METHOD OF NEUTRAL INTERLOCK IN THE PREVIOUSLY OFFERED CIRCUIT !!

A revised circuit has been drawn up and will be published soon.

Please email me or post here with any questions you may have.

Kind Regards, Andrew.

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Tri Pod Cars - Simple, light and fun.


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 Post subject: Re: Reverse fitment -
 Post Posted: Fri Jul 01, 2016 6:50 am 
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Joined: Tue Nov 27, 2012 11:59 am
Posts: 384
Location: Sunshine Coast, Qld
Speaking of actuators, it has been brought to my attention that it may not be immediately obvious that when setting up the 'throw' of the actuator and its stop position for appropriate drive into the final drive chain, that the actuator needs to actually switch itself off with its internal limit switch.

Otherwise it will be grinding away, and ultimately overheating.

Andrew.

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 Post subject: Re: Reverse fitment -
 Post Posted: Fri Jul 08, 2016 6:50 am 
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Joined: Tue Nov 27, 2012 11:59 am
Posts: 384
Location: Sunshine Coast, Qld
REVERSE WIRING UPDATE !

Having gone through the many possibilities and searching for appropriate hardware I feel the simplest and safest solution is to disable the 2 speed option and use either 12 or 24v permanently. I will post a link soon to the revised standard Tri Pod reverse circuit. To complete it you will need a isolation switch and a few terminals. Let me know if you wish to upgrade your reverse wiring and I will send out the parts and a hard copy of the circuit free of charge (to those who have purchased a reverse kit from Tri Pod Cars).

I can not source a high quality, high current solenoid that has an 80A rating (min) in both NC and NO positions suitable as a 12/24v changeover solenoid solution. I have re designed a two speed circuit though for those who wish to source the parts using two of the Cole Hersee high current solenoids we normally supply for the 24v switching and a few extra parts for safety. I will post this up in the downloads section in the next few days.

Interestingly Greg has let me know that he has quite happily just using the 12v setting (hasn't needed the extra grunt of the 24v mode) and has had a relay fail once, but in the same way as I have had in my experiments on the prototype (contacts just give up, ie no power being the result). Indicating to me that what happened the other day with a complete internal breakdown is unusual but nonetheless I feel we should take steps to avoid an embarrassing and possibly damaging incident.

Regards, Andrew.

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 Post subject: Re: Reverse fitment -
 Post Posted: Tue Jul 12, 2016 9:46 am 
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Joined: Tue Nov 27, 2012 11:59 am
Posts: 384
Location: Sunshine Coast, Qld
The revised standard Tri Pod 1 reverse circuit is now posted in the downloads area.

All builders and users of our reverse design please take a read of the NOTE below re high current draw of the 24v motor under stalled or very slow going high current usage such as back up a steep slope.

NOTE: The suggested (and supplied if purchasing a reverse kit from TPC) 24 volt geared 450W motor is more than capable of drawing 100 plus amps when stalled or fully loaded backing up a slope. Common sense should be applied to how long power is applied to the motor under these circumstances. I suggest 5 - 10 seconds max under stalled or high load conditions. The most likely outcome from excessive use in a high current draw situation is burnt windings in the motor. This is NOT covered by any warranty.

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 Post subject: Re: Reverse fitment -
 Post Posted: Tue Jul 12, 2016 10:52 am 
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Joined: Tue Nov 27, 2012 11:59 am
Posts: 384
Location: Sunshine Coast, Qld
Revised actuator control circuit now also uploaded in downloads section.

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 Post subject: Re: Reverse fitment -
 Post Posted: Fri Dec 02, 2016 1:49 pm 
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Joined: Wed Sep 02, 2015 3:25 pm
Posts: 84
Location: Leschenault Western Australia
Here is a link for the fitting of the mechanical side of things on a 'Busa based car.
viewtopic.php?p=967#p967
Cheers
Mal


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