(07-10-2015, 04:51 AM)hariram Wrote: Hi Peter
Thank you for all information !!!
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Now with the above information I am testing TCU but ideally i have no idea what should be the load,as it is directly connected to Track. Secondly as TCU has single side track its load should be half of TU.
I need more information regarding TCU testing in ideal condition.
Thanks
Hari.
From the picture you helpfully attached, I am a little bit confused and will need to check the literature.
I think that what you call a TCU I have called a TU= Tuning Unit (but the other Peter, probably more correctly, originally called a TTU= Track Tuning Unit)
I also agree your description of what is inside and what it does electrically.
However from your description of its use it does sound more like what I would call
ETU = End Tuning Unit.
I am familiar with the use of an ETU either -
a) as the connection for a Transmitter at the centre feed position of a pair of jointless tracks, or
b) the termination just prior to a block joint for the jointed variant.
Your description of utilisation agrees with b)
It does sound as if you are using the equipment in a configuration with which I am not familiar.
You are probably right; in my days the TI21 could only be used as a double rail track circuit.
However I do know that it can now be used through pointwork as a single rail track circuit but do not know what components are required for this; I shall have to bring my knowledge up to date and respond to you later.
But in the meantime, I still don't actually understand precisely your use of the word "load".
I agree that the track circuit would form the electrical load for the transmitter as seen via the various transformers etc. so I have no problem with the term in that context; however I do not comprehend why you would need to know its value when testing the track circuit set up. Please explain further.
PJW