Member postings for Peter Bell

Many thanks for the replies. Before I can do anythingI need to do is move my clock from the workshop near to where the pc lives, easier said than done, working on it but other things are to do first!

What I was hoping was extract the timings from the bdc sensor negative going pulse in the blue trace and see the speeding up and slowing down of the pendulum as the actuating coil switches. I've got a Microset and sensors, nice bit of kit but never had much success with it.

Peter

At least you didnt knock it over Dave, thats my normal trick!

Dont want to detract you but perhaps someone can help?

I would like to do some analysis on my simple clock (posted 9/9/20 doesnt time fly!) but your setup is way beyond me, is there any easy software I could use to plot my 1/2 sec pulses to give something like period variations?

Thanks Peter

My high friction clock with the pulse length sensing for amplitude control appears to have lost under1 minute since I reported it on this thread on 9th Sept so all things considered I'm quite pleased with that.

On another project I had light interference problems with the slotted switches so I made my own using OP 231 leds and OP800 as the phototransistor, think they are matched to 890nm from memory. Also had great success with AH1801 unipole magnetic sensors which are surface mount. Had some boards made, they are fairly sensitive and only around 20p each--probably discontinued now!

Peter

Michael,

Thanks for the link to austinmemories. I've often wondered what Longbridge was like, thanks to that excellent website I now know from start to finish!

Peter

Thanks Paul, saw that and bought one Friday,

Peter

Thanks everyone for the info.

Still looking for my motors but no progress, perhaps they may have gone in a tidyup.

Got some wiper/door motors but the majority don't have a plain output shaft so difficult to attach anything to also some door motors have a limited duty cycle and got very hot on previous use. A heater fan looks the most attractive and the older Smiths or Lucas have metal casings which are easier to mount, some of the modern variety seem to be built into the plastic mouldings. Lots on ebay but was intending visiting a local breakers and have a look. New motors on ebay abound but many look smallish and appear to be higher speed.

Peter

Thanks everyone, wealth of information! As I have no experience of these fans I have been drawing up the design put together by Brian Baker with view to cnc'n the parts and building one.

Thanks for the info on gas boiler exhaust fans, just realised I know someone who services has boilers for a living, he's bound to have something....

The fans on the boiler exhaust fans look rather small and curved, don't they soot up easier than the straight blades?

Peter

Just pm'd

Bill. Thanks for the advice on blades. I have looked at various fans in my life but never really understood why there are so many differences between them whe they are all doing the same job.

This design has 12 smallish blades, other designs have 6 deeper blades, is there an easy rule for efficiency on size and number also from what I have read how critical is the blade face to casing dimention?

Brian, I found the first part really useful where especially where you showed different examples of blowers, I had only ever seen them at a glance without taking a lot of notice!

Bernard, Thanks for the offer which I'd like to take up, shall I PM you?

Peter

Thanks Brian. Now located copies had a read, well written and all looks feasible. The size is fine, should be able to get the sheet parts profiled on a cnc mill. Cannot locate a 12v heater type motor at present, I have a few waiting for a project---if only I could find them!

Regards

Peter

Thanks Rob, Yes your right--thats what you get for reading postings without your specs!

Peter

Investigated a dead central heating pump but its getting a bit too heavy so coming out in favour of making the Brian Baker version in ME. Hope to track down the relevant back issues.

From a web search it looked like there maybe laser cut plates available?

Peter

Many thanks for the advice everyone, I'd never have thought of using pop rivets or a central heating pump! The straight blades makes it easier.

Brian, would apprecciate the details of ME your article was publised in? sounds an interesting read.

Regards

Peter

Hello, I want to build a steam raising type blower with a diameter of around 5" driven by a 12v variable speed motor on top.

Designs show various types of blades including straight ones. Has anyone built anything like this and can offer advice on blade construction and attaching the blades? Thanks

Peter

Thanks everyone for your help.  Perhaps I should have said it was on a test rig outside but I didnt think I needed to to ask about a fan!   Peter

Edited By Peter Bell on 21/09/2020 18:35:22

I have a vehicle type Webasto diesel heater which really does not like operating on a 3" dia vertical flue due to back pressure. I had thought of making a steam raising type blower with a variable speed 12v motor to put on top of the flue as an experiment. to create a slight negative pressure but have no experiance of these.

However on the steam raising designs looked at all the flu gas passes through the fan, is this decremental on the fan? Was going to put the motor on top

Are there are any alternative designs around using an ejector or similar which means the fan is on the clean cool bit just supplying air?

Can anyone offer any advice before I start? Thanks

Peter

Edited By Peter Bell on 21/09/2020 13:37:46

Edited By Peter Bell on 21/09/2020 13:38:37

Thanks everyone. We found some of the diodes are short circuit so we have some on order and are going to change these.

Many thanks John for offering the repair service--thought I had heard of somrthing like that before which is why I posted--you may be needed yet!

Peter

Not sure I dare try and do timings on my pendulum Dave!

Seeing your pics I couldnt resist looking at what mine looks like.

This one has the output from the sensor which is triggering the Arduino on theblue top line with the yellow energising coil on the bottom. The input pulse is quite long as the pendulum is jus swinging a small amout and gaining speed. The output pulse length is the yellow line and the energising coil is driven directly by the arduino.

The swing has increased and the pulse length has reduced to 21ms, the energising pulse is also reducing with less power being given to the pendulum.

Finally its got up to speed and the energising pulse is being switched off as the input goes under 21ms, the pendulum slows slightly input length increases and its energising again. Tried fiddling with the energising strength but with my high friction clock train it didnt make much difference.

Peter

The knife has a straight edge, Ive only ever seen straight ones. The knife moves doesn't downwards in a straight line but moves side ways as it descends and cuts.

Peter

Yes the cutting stick is important and readily available. When its worn the knife works in a groove rather than on a flat surface.

Maybe possible to hone it a bit but a properly ground knife makes a big difference.

Peter