[TR] Thermal Transmitter Temperature Sender help

[Sujit Roy]

Thanks. I have spare parts and I plan to create a setup on a bench. I have
some documents on how to check the gauge and voltage stabilizer and noe
some resistance no. If my set up models that of my stag. I will have some
sanity.  My stag has a 3 speed BW35. Box.  At around 70 mph the engine
speed is close to 4k rpm. Did the tr7 use a bw35. If so are these numbers
similar

On Sat, Aug 15, 2020, 10:35 AM DAVID MASSEY <dave1massey at cs.com> wrote:

> That could be problematic.  If the Stag gauges work like those in the
> TR4-6 there is a voltage stabilizer that maintains a constant average 10
> volts on the gauge.  But the original stabilizer is an early form of a PWM
> regulator.  The contacts will alternately apply full battery volts and zero
> on a proportional basis such that the average is 10 volts.  And the
> switching frequency is about one hertz.  The gauges react slowly enough
> that they average it out just fine but if you put a voltmeter on it you
> will see the voltage switching on and off fast enough that your meter won't
> have time to settle out and give a meaningful reading.
>
> There are after-market stabilizers available that use a solid-state IC
> voltage regulator providing a constant 10 volts.  If you have one of those
> you could get a reliable reading.  But that is if you have one of those.
>
> All that said, if I had a resistance value for the gauge I could calculate
> what you would get if an IC stabilizer was installed.
>
> Dave
>
>
>
> -----Original Message-----
> From: Sujit Roy <triumphstag at gmail.com>
> To: DAVID MASSEY <Dave1massey at cs.com>
> Cc: Triumphs <triumphs at autox.team.net>
> Sent: Sat, Aug 15, 2020 11:30 am
> Subject: Re: [TR] Thermal Transmitter Temperature Sender help
>
> Follow up question. Does anyone have data showing what the voltage at the
> gauge should be  to resistance values.
>
> On Fri, Aug 14, 2020, 12:15 PM DAVID MASSEY <dave1massey at cs.com> wrote:
>
> Here are some data for the TR8.  This might be close enough for the stag:
> Temp C    Temp F    Orig ohms   GTR110 ohms
> 50        122       332         290
> 55        131       275         242
> 60        140       227         197
> 65        149       193         169
> 70        158       158         142
> 75        167       134         120
> 80        176       114         102
> 85        185       99          91
> 90        194       85          77
> 95        203       74          65
> 100       212       60          55
> 105       221       51          48
> 110       230       44          41
> 115       239       37          37
> 120       248       32          31
> 125       257       28          28
> 130       266       24          25
> 135       275       21          22
>
>
> If you have a source of resistors in this value range you can connect them
> in lieu of the sensor and check the reading to see if it is close.
>
> Dave
>
>
>
> -----Original Message-----
> From: Sujit Roy <triumphstag at gmail.com>
> To: Triumphs <triumphs at autox.team.net>
> Sent: Fri, Aug 14, 2020 11:31 am
> Subject: [TR] Thermal Transmitter Temperature Sender help
>
> I'm going to try and figure out if my Stag is running hot. The gauge
> always reads high
>
> I found a note on another forum on how to test the voltage regulator, and
> another forum how to calibrate the gauge.
>
> I'm trying to figure out how to test the Thermal Transmitter Temperature
> Sender. Does anyone have any data on how the resistance changes with
> temperature?
>
> Since most Triumph around the 70's used Smith gauges, I'm assuming the
> data for the  Thermal Transmitter Temperature Sender would be the same.
>
> Regards, Sujit
>
> --
> Sujit Roy
> Cupertino, California
>
> https://triumphstagblog.wordpress.com/
>
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