Ransomes T51D - Right hand Deck blades engage but stop as soon as the rocker switch is released.

[soulman]

New issue on my Ransomes T51D Wide area mower with a Kubota Engine. It has 3 decks, front, left and right. The issue i have is that when i press the rocker switch to activate the right hand deck, the red light on the rocker switch is illuminated and the deck blades start rotating but as soon as i let the rocker switch return to it center position (spring loaded to center position) the right deck blades stops rotating. The blades will continue to run while i hold the rocker switch down. The other two decks are working fine. I replaced the rocker switch with a new switch to rule that out as the switch was a bit stiff but issue still remains after the new switch was fitted. I had a look at the electrical drawing and i saw that there is a relay for each deck and i interchanged the front deck relay with the right deck relay but issue is still there. I did a test where i just turned on the ignition key and then pressed the rocker switch to engage the blades on each deck. I could hear the relays engage but it seems that the right deck relay engages but does not remain engaged. The behaviour of the other decks if different. The relays for those decks seem to engage and remain engaged until the rocker switch is depressed in the other direction, which is obviously normal behaviour.

it doesn't appear to be the caused by the deck inhibitor switch as i found that if u do engage the blades and hold down the rocker switch on the console panel and then press that inhibitor switch while the blades are engaged, the blades cut off immediately so it looks like that is operating correctly. I'll check the resistance of the inhibitor switch just in case.

Would anyone have an idea of what might be wrong with the right deck or how to proceed to further debug the issue?

 

[forblue]

I would have thought there must be a capacitator to keep relay engaged when switch is released, try to trace wiring on the other decks if necessary swop over relays and or switch to check.

 

[soulman]

I dont see any obvious sign of capacitors in either the wiring diagram or on the machine. Not quite sure how the relay circuit stays energised until the rocker switch on the console panel is flipped to off position.

 

[Kevm]

The relay must be latched somehow if the switch circuit is broke when you release the switch, does the light remain on? make sure the switch is working the same as the others.
If there is nothing wrong with the switch then start looking at how the relay is meant to remain energised, there must be power to it to keep it engaged.

 

[soulman]

Kevm, i actually replaced the original rocker switch with a brand new switch of same part number so i'm confident that the switch is not at fault. the light goes off as soon as the deck blades disengage. I'll do as u say, try to figure why the relay is not staying engaged. I am lucky that there are two other identical circuits to compare with i guess, ie the the front and left side decks.

 

[Kevm]

Yeah I know it's a new switch but is it working right, wouldn't be the first time, check it with a meter.
I would think that power comes up to the switch and connects when you push the switch forward and stays connected when you let go, then breaks the circuit when you push the switch the other way.
If the switch only has two connections then it must work like that, unless there is some complicated electronic wizardry going on.

 

[soulman]

seems spec says switch is Momentary on - o - Momentary on I→0←II

Britax/SWF 511-212 Rocker Switch Illuminated 12v and 24v versions | DMComponents

Change - over contact switch Spring loaded - to centre Switch Maximum Voltage/Load 12v: 16 A 24V: 8A Funtion: Momentary on - o - Momentary on I→0←II 511-212 12v Illuminated - General 511-213 24v Illuminated - General For Switch and Pilot lamp accessories, insert/symbol options please...

dmcomponents.co.uk

according to wiring diagram for the switch, wires connect to 3, 6, 7 and 8 (note 9,10 is the sw light)

 

[Kevm]

According to that schematic and if you are only using pins 3,6,7 and 8 when you push the switch to position 1 you are actually breaking the circuit.
It makes more sense if position 2 is on and position1 is off, but I am still not sure how that works with a standard relay.

 

[Rust]

Best idea it to swop left and right switches. Then relays. Use what you've got and know it works !

Any safety switches?

 

[Nearly]

@Dave W

 

[soulman]

@Rust .. Tomorrow i will start debugging from the rocker switch to see if i can find the issue.

it doesn't appear to be the caused by the deck inhibitor switch as i found that if I do engage the blades and hold down the rocker switch on the console panel and then press that inhibitor switch while the blades are engaged, the blades cut off immediately so it looks like the inhibitor sw is operating correctly.

 

[soulman]

i did some debugging and it is working again. looks like it was a bad connection on the relays where they plug into the holders.