30Int and BT30 Tooling

On Sat, 12 Feb 2005 19:52:07 GMT, Peter Sheppard wrote: Can you have the batteries, effectively in

Changing my hat to battery charger manufacturer:

Charging batteries in series is fine as long as certain requirements are met, and constant current charging is best, thus ensuring that all cells get the current through them, but it does need monitoring. Constant voltage is fine but you will probably need to equalise the cells every so often as they will get out of charge balance with each other.

Charging batteries in parallel is a bit of a no-no, as you cannot guarantee that each battery is going to receive the charge it needs. Also, it is possible for batteries in parallel to 'cycle-down' by interbattery discharging, so steering diodes are 'usually' fitted into series-parallel battery banks.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

Hang on a minute, mate. Some of us enjoy a full & frank relationship with our wives! :-) Workshop equipment is designated as labour saving devices and as such needs to be updated regularly, so that outdated equipment doesn't cause overly prolonged absences from our good ladies" company.. Sound plausible? Works for me. :-)

Tom

Peter

Are these *large* (ie up to 1 1/4", & quite rare in 30 int) or Medium (up to 1", much more common, but for some reason often come with metric collets only) ??

I wouldn't mind picking up a Large Autolock in 30 int, I've got one but it's been in a severe crash & the shank is bent. No it wasn't me .

Also I want a small autolock in QC30, you can tell these because there's a driving collar distinct from the main body, whereas the ordinary 30int autolock just has slots in the body. Either that, or imperial collets for the anonymous collet holders I do have. I think these are similar to the old C type clarkson, they have in effect a driving peg at the threaded end of the collet rather than the flanged end of the S type.

Not sure what you mean by expanding collets in this context?

Cheers Tim

Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service

I wasn't measuring at the time, just noticed them. There were also a couple of flycutters, one of which I'll probably take later.

We believe you !! :-))

I didn't have a long sort through as Les had already dug out a small selection before I got there.

Like the R8 collets on this auction:

I left my spanner for the Clarkson behind, so I will be going back again. Let me have a wish list and I'll see what I can pick up.

The bl**dy cat was underneath my desk on my first attempt to reply, but she trod on the mains surge arrestor/distribution board switch and cut the supply to the pc's and network!

Ever seen a cat fly? boot propelled :-))

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

I thought that "Stumpy" had hydraulic control for forward/reverse?

Peter Sheppard wrote: .................................

Addressing just the one point. Mercedes Benz trucks (60-70s) had a parallel-series switch connected to the batteries that switched the 12v system to 24v only for starting.. A visit to a truck "breaker" might be fruitful.

Tom

The website is live!!!

Have a look at

Cheers

Peter

Stumpy does, but it is all nicely contained in an "Eaton" unit. I have a lever that you move forward to go forward and back to go back!

What I am proposing is a hydraulic pump, motor, valves, filters, reservoir et. etc. I don't know what I need and I was hoping that someone had been down this route before!

Cheers

Peter

Nice site, but somebody shoot that bloody pheasent!

Regards

Kevin

First we need to throw a few things over the calculator..

What's required is the rated capacity of the pumps: GPM at what pressure and what type of pump are they? Are the motors rated for continuous use or intermittent? What would be the estimated hp (at the drivers) needed for tractive effort? What diameter wheels and top speed required?

Tom

Apologies for the delay, the day job took me away for a couple of days!

Rated Capacity - haven't a clue. They are bolted on the end of a Lansing Bagnall motor. The motor is rated at 4.5HP for 10 minutes at

(GPM - gallons per minute?)

The hydraulic motors I am looking at are reversible and rated at, 650 RPM @ 6.5 GPM (25 LPM), 2750 psi max. operating pressure, 733 in-lb of torque.

The wheels are around 5", so at top RPM would give a max speed of

What would the hydraulic circuit look like? Pump, reservoir?, valves to direct the flow forward/reverse? I assume that all you do is reverse the feed, so there needs to be a return path?

Cheers

Peter

I had another look through the box last night, and the expanding collets are Erickson DA or Double Angle types, of 3 body size ranges, and the holder is for the largest. The smallest is the type that goes into the extension holders that Kennametal make.

I'll be looking out for the next sized holder down when I go back to see Les.

The sheel cutter holder with cutter in place was the smallest Clarkson Dedlock holder.

Peter

-- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk

Tom,

Thanks for that. How have you quoted the flow from the pump? Is that based on the kW of the electric motor? If you have found details of the pump, could you point me to them?

With regard to cooling. The run (at present) is at most 5 minutes and not all of that will be on full load, so the 10 minute 4.5HP max rating shouldn't be a problem.

If your figures are correct, should I look at a 2:1 step up between the motor and the axle (as you seem to predict that I will only achieve 50% of the rated output)?

They are Lansing Bagnall "badged" motors, I was told that they came from a stacker truck (but that was un-corroborated).

I was going to control the speed of the electric motor to control the speed, would I still need a flow control valve?

Cheers

Peter

At 24V, sounds like they are are out of an electric pallet truck..

Bit of a mismatch though, as the electric motor equates to 3.36 kw and the hyd/motors at full capacity at 5.54 kw.

Doing the calcs, the pump @ 2750 psi, delivers 10.62 litres so falling short of maximising the performance of the hyd/motors, at 276 rpm.

A problem with using intermittent duty motors, is the off duty cycle delay while they return to ambient temperature.

Apart from what you list above, a flow control valve in the circuit would allow smooth takeoffs.

Tom

Yes, I worked on the hp & psi to get the flow, however I might be a trifle high on the flow as I later found some for sale that were listed at 200 bar. No free lunches with hydraulics, so you will have to gear up, if you want that speed.. Of course this carries the caveat of torque reduction at the drivers. If you can control the electric motor that would eliminate the flow control valve. All you need now is a open centre motor control valve. These have a motoring spool that will allow the motor to free wheel in neutral. Whereas a conventional valve would stop the motor when in neutral, however, considering the flows involved you possibly could use one and gain the benefit of using it to provide braking.

Tom

Subject: Re: Build 'em big!

Probably used a formula like

P=V(dot) p where P is power, V(dot) is volumetric flow rate and P is pressure. throw in a fudge factor for pump efficiency.

The problem is the formula only works if you use a consistent set of units ( metric , use power in whats, volume flow in cubic meters per second and pressure in pascals )

Unless you have a spare pump I would go the other way round, motors are cheaper than pumps, and electric overload protection is fairly cheap and simple.

When you say double ended do you mean a pack etc at each end ?

The railcar will carry up to 8 people (including driver), so a

Lets allow a 1:20 gradient, 2% rolling resistance, at 10 mph.

tractive force = ( 900 / 20 + 900 x 0.02 ) x 9.81 = 620 N

speed ( 10 mph ) = 4.47 m/s

delivered power = 2.8 kW ( = 3.7 Hp )

to allow for getting up to speed you will need a bit more, say 5 Hp.

If I'm right about the efficiency of hydraulic pumps and motors you would need a very big electric motor ( 50 Hp ?? )

Anyone got figures on hydraulic efficiency ??

At 733 lbin working a 5" wheel you have 293 lbf ( = 1300 N ) available from a single motor, but you only need about 800 N to provide reasonable acceleration, so about 2/3 of the maximum pressure will be needed to run the motor, or 1/3 if two motors are being used.

Power electronics are quite expensive in comparison to hydraulic restrictors, but restrictors make a system very inefficient.

When you start looking at the detail you realise why about the only vehicles that use hydraulic drives are diggers ( they only need to move a little every now and then, and already have a hefty hydraulic system they don't need to use for digging when on the move ).

not

Jonathan

Barnes's theorem; for every foolproof device there is a fool greater than the proof.

To reply remove AT

Power in 'whats' !!

Mr Watt must be turning in his grave...:-))

Peter

-- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk

Dyslexia ???? strikes again K.O.

apologies to Mr Watt

"volume flow in cubic meters per second" Yeah right..