Comments on: RGE on Tenterhooks! http://www.racinggreenendurance.com/blog/?p=1348 Fri, 20 Jan 2012 15:20:06 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: Gordon Hamm http://www.racinggreenendurance.com/blog/?p=1348&cpage=1#comment-2279 Gordon Hamm Fri, 24 Sep 2010 13:19:32 +0000 http://www.racinggreenendurance.com/blog/?p=1348#comment-2279 Do you have a hand crank megger to check for insulation break down? Does the magnetic contactor have over load heaters? You could have a motor problem. Do you have an amprobe to check the current draw by the motors? If you have motor bearing problems it will cause the over load heaters to open the circuit. Are you using mechanical relays or solid state relays in the control circuit? If mechanical clean the contacts or replace the relay. You push the start button, the contactor closes, but soon as you release the button, the contactor opens. If the mag will will not hold there is an open in the control circuit or the mag holding contact is dirty or badly pitted. Here is a website that shows the basic of a motor control circuit. http://www.allaboutcircuits.com/worksheets/acmcc.html Do you have a hand crank megger to check for insulation break down?
Does the magnetic contactor have over load heaters? You could have a motor problem.
Do you have an amprobe to check the current draw by the motors? If you have motor bearing problems
it will cause the over load heaters to open the circuit.
Are you using mechanical relays or solid state relays in the control circuit? If mechanical
clean the contacts or replace the relay.
You push the start button, the contactor closes, but soon as you release the button, the contactor opens.
If the mag will will not hold there is an open in the control circuit or the mag holding contact is dirty or badly pitted.
Here is a website that shows the basic of a motor control circuit. http://www.allaboutcircuits.com/worksheets/acmcc.html

]]> By: Charles H Schulmann http://www.racinggreenendurance.com/blog/?p=1348&cpage=1#comment-2241 Charles H Schulmann Thu, 23 Sep 2010 14:41:46 +0000 http://www.racinggreenendurance.com/blog/?p=1348#comment-2241 Dear RGET , another possibility which is an extension of our previous comments is given the harsh treatment that the SRzero has had , Check for contactor coil continuity . Brittle cable insulation offers a number of unreliable electrical and mechanical properties to say the least – checking is needed for all unchanged cables . Sometimes the integrity of the insulation can deteriorate fairly quickly given the right conditions . We recycle for manufacturing soles , Polyvinyl Chloride ( P.V.C ) which is used in many cable insulations , where we have found that some of this P.V.C insulation does not offer the appropriate mechanical and electrical characteristics because the cable manufacturers add a lot of filler material to cut costs . More remote but very possible is the viral attack of P.V.C which cause insulation barriers breakdown of the cable , again given the right conditions a bit like the book “ The Andromeda Strain ” . These viral causes are well documented . Nothing is impossible and should be considered . Best regards from Ladysmith ( Kwazulu Natal ) in South Africa , Charles and friends . Dear RGET ,
another possibility which is an extension of our
previous comments is given the harsh treatment that
the SRzero has had , Check for contactor coil continuity .

Brittle cable insulation offers a number of unreliable
electrical and mechanical properties to say the least –
checking is needed for all unchanged cables .
Sometimes the integrity of the insulation can
deteriorate fairly quickly given the right conditions .

We recycle for manufacturing soles , Polyvinyl Chloride
( P.V.C ) which is used in many cable insulations , where
we have found that some of this P.V.C insulation does not
offer the appropriate mechanical and electrical characteristics
because the cable manufacturers add a lot of filler material
to cut costs .

More remote but very possible is the viral attack of P.V.C
which cause insulation barriers breakdown of the cable ,
again given the right conditions a bit like the book
“ The Andromeda Strain ” .
These viral causes are well
documented .

Nothing is impossible and should be considered .

Best regards from Ladysmith ( Kwazulu Natal ) in
South Africa , Charles and friends .

]]> By: Graham Blackwell http://www.racinggreenendurance.com/blog/?p=1348&cpage=1#comment-2240 Graham Blackwell Thu, 23 Sep 2010 14:14:45 +0000 http://www.racinggreenendurance.com/blog/?p=1348#comment-2240 Does the contactor have its own power source, to keep the contact closed? Is there a fuse blown somewhere thats interrupted the power to the contactor? Does the contactor have its own power source, to keep the contact closed?
Is there a fuse blown somewhere thats interrupted the power to the contactor?

]]> By: Charles H Schulmann http://www.racinggreenendurance.com/blog/?p=1348&cpage=1#comment-2239 Charles H Schulmann Thu, 23 Sep 2010 13:45:34 +0000 http://www.racinggreenendurance.com/blog/?p=1348#comment-2239 Dear RGET , was the recalcitrant contactor compromised in any way by the fire or by the heat of the fire ? We have found in the past that the casing of some the contactors who are subject to switching regularly where there could be relatively high currents can become doped as in a semi conductor due to insufficient quenching of the spark between the contactor’s metal terminals which increase with humidity and heat which can then become obstreperous when they need to make contact where they either stay switched on or refuse to stay on , depending on the immediate control circuit and the doping . Another less obvious occurrence is when the lugs which are screwed to the terminals crack at the end of the cable or wire metal harness and makes an intermittent infuriating connection which is not visible unless you remove all the leads to the contactor including particularly the coil control leads which have the knack of cracking due to vibration in such a way that it is invisible but totally debilitating . Process of elimination like removing the intractable culprit and isolating it in a corner so to say and testing it if it can behave on its own . Is the contactor control circuit reliable ? We shall not monopolize you any longer , we hope that you will uncover the mystery . Wishing you all the best , from Ladysmith ( Kwazulu Natal ) in sunny South Africa , Charles and friends . Dear RGET ,
was the recalcitrant contactor compromised in any
way by the fire or by the heat of the fire ?

We have found in the past that the casing of some
the contactors who are subject to switching regularly
where there could be relatively high currents can
become doped as in a semi conductor due to insufficient
quenching of the spark between the contactor’s metal
terminals which increase with humidity and heat which
can then become obstreperous when they need to make
contact where they either stay switched on or refuse
to stay on , depending on the immediate control circuit
and the doping .

Another less obvious occurrence is when the lugs which
are screwed to the terminals crack at the end of the
cable or wire metal harness and makes an intermittent
infuriating connection which is not visible unless you
remove all the leads to the contactor including particularly
the coil control leads which have the knack of cracking
due to vibration in such a way that it is invisible but
totally debilitating .

Process of elimination like removing the intractable culprit
and isolating it in a corner so to say and testing it if it
can behave on its own .

Is the contactor control circuit reliable ?

We shall not monopolize you any longer , we hope that you
will uncover the mystery .

Wishing you all the best , from Ladysmith ( Kwazulu Natal )
in sunny South Africa , Charles and friends .

]]>