Convert 1975 Afron Cherrypicker?

Technical discussion on converting internal combustion to electric
Trogdor!
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Convert 1975 Afron Cherrypicker?

Post by Trogdor! » Thu, 15 Sep 2011, 05:09

It's like the one on the left - if you look at part 20 you can kind of see the raised bit that goes into the housing and presses against the bearing. Part 21 has the same.

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Convert 1975 Afron Cherrypicker?

Post by Adverse Effects » Fri, 16 Sep 2011, 00:58

ok now the end float is going to be a lot harder to explain

With the output shaft in place, the rest of the casing can be fitted, and the no hole end plate. These should be fitted with out the gaskets, and as you torque up the end plate this will push the output assembly towards the the wheel side.

Now, at the other end of the shaft, install the other end plate Without the gasket and tighten the bolts to the just bite point again, using feeler gauges measure the gap

the gap is X thou, what you need to do is take that away from the compressed width of a gaskets, Y thou, which leaves Z thou end float. The preload on the bearings is about to 4 to 5 thou, so you need to add the end floatZ to the preload 4 to 5 thou which gives the thickness of the total gaskets required, then you have to work out how meay go on each end Image

a paper gasket will crush about 50%

now disassemble the casing, and oil soak all the gaskets and rebuild. This helps with making it seal

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Convert 1975 Afron Cherrypicker?

Post by Trogdor! » Fri, 16 Sep 2011, 15:58

Brilliant - thanks for all that. So the fundamental thing is that the bearings should have 4-5 thou of preload.

So if I have this right, I measure the gap X with no gaskets, subtract 4 or 5 thou from X and the result is the compressed thickness of the gaskets required?

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Convert 1975 Afron Cherrypicker?

Post by Adverse Effects » Sat, 17 Sep 2011, 22:49

that is bout right yes

hehe its so much harder to teach through text then hands on lol
Last edited by Adverse Effects on Sat, 17 Sep 2011, 12:50, edited 1 time in total.

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Convert 1975 Afron Cherrypicker?

Post by Adverse Effects » Wed, 28 Sep 2011, 16:39

so how did you go with getting it set up right

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Post by Trogdor! » Wed, 28 Sep 2011, 19:23

I only got onto it yesterday when I had the machine apart to send one arm to the sheet metal people to make up covers for the motors.

Got 2 new bearings, with the 2 halves put together with a smear of RTV silicone between (no gasket) and fully cranked down, the cups were held but not very tightly - they moved with a light tap.

I then removed the gaskets from the end plates, attached the back plate and bolted fully down, and then attached the output side plate, and bolted down firmly to the point where the shaft seemed locked up tight, I got a clearance of 0.7mm (sorry, I don't do thou). If I take off 0.1mm as suggested, that's 0.6mm, or 0.3mm of gaskets each side.

I measured the gasket I'd previously used at 0.4mm.

My conclusion was that the gaskets I had probably where close enough, I just needed to squash them a bit more, so I put them back on.

I've cranked down the plates until the input shaft takes a bit of effort to turn - before it was turning fairly freely. If I crank them down more the shaft becomes increasingly hard to turn, but I'm not sure what's enough or too much. There's definitely more preload on the bearings than before.

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Convert 1975 Afron Cherrypicker?

Post by Adverse Effects » Thu, 29 Sep 2011, 03:46

well it sound like you may be loading to much

the 5 thou is from the point where the bearings touch solid but not squeezing yet

that is what preload is its how much you squeeze the bearings
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Post by Trogdor! » Sat, 01 Oct 2011, 02:33

You might be right - I had a chat to the neighbour who's a fitter & turner and didn't have much experience with these bearings, but referred to a section of a book he had that talked about doing up trailer bearings, where it said you tighten the castellated nut until the washer under it is just being gripped - what I didn't check in his book was whether you then tighten or loosen it to get the split pin to go through.

My current plan is to back off the pressure until the input shaft just starts to turn easily, which should put me in the ballpark. The machine travels at a relatively low speed, and the bearing is pretty chunky at 80x40x19.75mm, so even if the preload is a fraction high, I don't think there'll be a problem with it overheating from excessive friction.

I'm starting to think that it's probably likely that I didn't cause the bearing to fail, rather that it was already dead not having been replaced in the machine's 36 year life, as you'd never have heard it creaking over the noise of the IC engine.

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Post by Adverse Effects » Sat, 01 Oct 2011, 07:12

Trogdor! wrote: what I didn't check in his book was whether you then tighten or loosen it to get the split pin to go through.


you turn it to the cloest one you can get to

but that has nothing to do with this
My current plan is to back off the pressure until the input shaft just starts to turn easily, which should put me in the ballpark.


ok over tighten the bolts to the point that the input shaft takes about 2 times the effort to turn as to when its not tightened up

make sure you turn the input shaft enough til the out put shaft turns at lest 1 full turn

then back off the bolts on the flange till there lose (do not turn any shafts at this point)

now do up the flange bolts to about 10 to 20 pounds torque

this is the point you measure the gap and you work out the end float
The machine travels at a relatively low speed, and the bearing is pretty chunky at 80x40x19.75mm, so even if the preload is a fraction high, I don't think there'll be a problem with it overheating from excessive friction.


speed is not the only thing that trashing a bearing, speed is only 1 of the digets in the equation

its like preload X lubrication X speed X environment sort of thing

you can have a bearing that only revolving at 1 RPM and i bet i could get it to collapse in less than 10 seconds

the shiny coating on all of the barrels in the bearing is what fails and its only like a chrome coating

this is why preload is so crucial

its like a tire on a car
to low pressure it wares on the out side edges
to much pressure and it wares on the middle

both will make it fail before it should

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Convert 1975 Afron Cherrypicker?

Post by Trogdor! » Thu, 13 Oct 2011, 02:02

I'm leaving the preload business aside for the moment while I sort out the final wiring of the machine.

My next quandary is earthing. The machine will have 3 Kelly controllers running off 48v, a 48v to 12v DC-DC converter for accessories, and a 48v to 240v AC inverter for power tools.

Does anyone know what the convention is for earthing? I initially thought the Kelly controllers didn't like it, but it turns out I was looking at a circuit diagram that didn't apply in this case.

So far with just the motor controllers, I haven't connected anything to the chassis, but wonder whether I should connect the -ve of the battery pack to the chassis, the -ve of the 12v converter and the earth of the 240v inverter. Whatever I do, the 240v inverter will be grounded for safety reasons (and there'll be an RCD on its output), but is there any point or benefit for the 48v and 12v supplies?

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Convert 1975 Afron Cherrypicker?

Post by Adverse Effects » Thu, 22 Dec 2011, 19:51

been a wile since an update on this

how did / is it going?

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Post by Trogdor! » Mon, 26 Dec 2011, 21:22

Image
Image

Before and after :)

That's the machine today doing work in the orchard. I've added a bunch more pics to the blog:
http://e-afron.blogspot.com/

In short, the machine is brilliant, pretty much exceeding all expectations. The final improvements were getting the arm bushes fixed up to stop the whole lot wobbling - a quick trip over the road to a neighbour with a machine shop and some reaming and turning soon had that sorted. The variable speed on the hydraulic lift is really nice.

While it normally uses a fraction of its potential power, on a few occasions I've been grateful for the excess grunt when driving up very steep slopes/ramps.

Apart from adding some more features, such as a mains inverter, I would like to improve the braking system, as it's currently not ideal.I posted a bit on how it works here:
http://e-afron.blogspot.com/2011/09/put ... ck-on.html

It kind of works, but there's still the possible situation while driving down a steep slope, if you release the foot switch the controllers drop out and you lose motor braking and the machine may still freewheel.

I'd really like to modify the brakes to have them held on by stronger springs and released when the foot switch is activated - ie. fail-safe brakes like trucks use.

For the moment the machine is rarely on steep terrain, so it's not so much of a concern.

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Convert 1975 Afron Cherrypicker?

Post by woody » Tue, 27 Dec 2011, 13:33

Nice! Looks really good :-)
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Convert 1975 Afron Cherrypicker?

Post by Electrocycle » Wed, 28 Dec 2011, 02:51

that's a serious improvement!

glad to have helped out a little bit :)
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Post by Adverse Effects » Sat, 31 Dec 2011, 18:43

that is looking so much cleaner and you would not pick it to be gasless

all in all well done it is something you can be proud of

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Convert 1975 Afron Cherrypicker?

Post by oldtrack123 » Sun, 17 Jun 2012, 05:37



Hi
Perhaps a bit late but still important

It should be pointed out that the earthing & neutral should not be interfered with/altered except by a licensed electrician
The correct fiting of a RVD ,now referred to as a "URCD"shall only be done by a licensed electrician
NO portable inverter in Aus should have an earthed neutral, except with an inverter or generator ,which is PERMANENTLY & CORRECTLY WIRED so RCD is fully operational
That requires special wiring

Any inverter which has an internal connection between the 240v & the 12v is a potential death trap & should be destoyed & disposed of

Such are no longer sold in AUS but may still be available from overseas ebay sites SO BEWARE
It would seem one such inverter is being discussed here since there is a problem if the vehicle has a neg earth & the inverter is in contact with the vehicle chassis

Other rules are
Do not deliberately connect the inverter to mother earth by an EARTH STAKE OR OTHER means.
For Max possible saftey [if not permanently wired ]
only connect ONE Class1 appliance @ any time [Class1 has a 3 pin plug

Multiple Class 2 [2pin plug are OK
Portable outlet boxes with in built RCDs give absolutely no protection!!

Peter
Last edited by oldtrack123 on Sat, 16 Jun 2012, 19:59, edited 1 time in total.

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Convert 1975 Afron Cherrypicker?

Post by oldtrack123 » Sun, 17 Jun 2012, 05:54

Trogdor! wrote: Whatever I do, the 240v inverter will be grounded for safety reasons (and there'll be an RCD on its output), but is there any point or benefit for the 48v and 12v supplies?



Hi
YES the inverter case should be connected to the main frame
But if you are simply using a plug in type RCD protected box the RCD will not be functional
The only way that can be legally done is by having a RCD permanently wired & permanently fitted to the INVERTER
Such work shall only be done by a licensed electrician who would also need to check that the inverter is suitable for fitting a RCD [some are not] & for the CORRECT TYPE of RCD
Peter

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Convert 1975 Afron Cherrypicker?

Post by RustySpark » Mon, 18 Jun 2012, 02:23

oldtrack123 wrote:   
YES the inverter case should be connected to the main frame
But if you are simply using a plug in type RCD protected box the RCD will not be functional
The only way that can be legally done is by having a RCD permanently wired & permanently fitted to the INVERTER
Such work shall only be done by a licensed electrician who would also need to check that the inverter is suitable for fitting a RCD [some are not] & for the CORRECT TYPE of RCD
Peter


Hi - I'm the OP - I lost track of my login details so I created a new ID.

Since I posted the questions regarding the use of an inverter, I was pointed to the regulations regarding earthing generators in another forum.

However, it is a bit challenging translating those regs to a specific application such as this, and finding a sparky who knows them and can do the correct modifications to the unit plus install an appropriate RCD seems highly unlikely.

My current take on all this is that I'm best off leaving the inverter as-is, apart from bonding the earth pin to the body of the inverter unit and to the chassis, although without an N-E link, the earth is not protective in any sense that I can see. On the other hand, the supply is floating (checking the output showed no potential between it and the battery input) so in a sense is inherently "safe" from faults to earth, be they via cable abrasion or human.

The tools currently used on this machine are all double-insulated (chainsaw and hedge trimmer), and pretty much all other tools are likely to be as well.

At the moment the inverter is temporarily installed with a extension cord looped up to the operator basket. I'd like to run the mains cable inside the boom and have it terminated at an IP-rated GPO, and am happy to have a sparky do the wiring of course, but the question is, is it OK to have a plain 3-pin plug connection to the inverter that is then run through the boom to this fixed GPO, or does the connection to the inverter have to be hard-wired?

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Post by oldtrack123 » Mon, 18 Jun 2012, 03:47

RustySpark wrote:
oldtrack123 wrote:   
YES the inverter case should be connected to the main frame
But if you are simply using a plug in type RCD protected box the RCD will not be functional
The only way that can be legally done is by having a RCD permanently wired & permanently fitted to the INVERTER
Such work shall only be done by a licensed electrician who would also need to check that the inverter is suitable for fitting a RCD [some are not] & for the CORRECT TYPE of RCD
Peter


Hi - I'm the OP - I lost track of my login details so I created a new ID.

Since I posted the questions regarding the use of an inverter, I was pointed to the regulations regarding earthing generators in another forum.

However, it is a bit challenging translating those regs to a specific application such as this, and finding a sparky who knows them and can do the correct modifications to the unit plus install an appropriate RCD seems highly unlikely.

My current take on all this is that I'm best off leaving the inverter as-is, apart from bonding the earth pin to the body of the inverter unit and to the chassis, although without an N-E link, the earth is not protective in any sense that I can see. On the other hand, the supply is floating (checking the output showed no potential between it and the battery input) so in a sense is inherently "safe" from faults to earth, be they via cable abrasion or human.

The tools currently used on this machine are all double-insulated (chainsaw and hedge trimmer), and pretty much all other tools are likely to be as well.

At the moment the inverter is temporarily installed with a extension cord looped up to the operator basket. I'd like to run the mains cable inside the boom and have it terminated at an IP-rated GPO, and am happy to have a sparky do the wiring of course, but the question is, is it OK to have a plain 3-pin plug connection to the inverter that is then run through the boom to this fixed GPO, or does the connection to the inverter have to be hard-wired?


Hi Rusty
Yes, only earth the "frame" of the inverter to to the chassis
The earth pin of the inverter should already be connected to the frame internally
If you use any form of metal enclosure for weather protection make sure IT &the inverter frame are bonded to the main chassis
Do not attempt in anyway to make an external earth to neutral link
By Aus Standards it must only be made internally & only IF a RCD is permanently fitted & wired to the inverter

NOT PLUGGED IN
You did well to check the output & since it shows no potential from either line to earth it is fully isolated [:)]
IF you are going to only use double insulated tools ^ take care with all leads & you should be quite OK
RE the cable through the boom
I assume when you refer to mains cable you mean from the inverter output to an accessable outlet on the boom
I see no problem that as long as the cable it is well protected from damage in conduit /flexable conduit etc.
The outlet as you have said needs to minumim IPx4 rating & must be double pole switching
The plug , socket @ the inverter & inverter would need to be IPX4 rated unless all is in a weather proof area

If you use any form of metal enclosure for weatherproofing, ensure it & the inverter are bonded to the chassis

Just one point which many do not understand A fully isolated inverter or generator is quite safe from shocks to earth AS LONG AS A FAULT DOES NOT DEVELOP AN EARTH TO NEUTRAL BOND
if that occurs you have no RCD protection with all the inherant dangers of an EN source
That is why the safety recommendation is to NEVER connect more than ONE Class 1 device @ ANY TIME
I think you understand that from your posts ,but many do not.
Anotherb poster mentioned a RVD from "powerstream"
A superior unit is expected to be available shortly from them called a URCD
It does not require an earth to neutral bond to be permanently made & possibly will be in a plug in form similar to Ampfibians but unlike them fully operational with an isolated power source
I was going to reply to your other questions regarding the 12v & 48V DC earthing but I expect you have sorted that out
Just remember you do not want high currents flowing through bearings etc
I suggest you do not use frame as negitive returns but direct cable both pos & neg to all
Peter

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