Member postings for Robert Atkinson 2

Cam followers are similar to the track rollers I liked to previously but typically have a slightly crowned otter surface

**LINK**

Have tried applying load to the sides and front edge of the seat to see if you are getting some kind of locking up? A load directly on the cross member with the nut will tell if it's the screw that the issue.

Do you have a proper thrust bearing at the bottom of the threaded rod?

If you can put an ammeter in series with the motor that will give you a direct indication of the motor torque and you can see the effect of putting the same load in different places.

Robert G8RPI.

My pet peeve is people saying something is tested and working when there ar obviously crtitical parts missing or broken or/and they clearly have no idea what the thing is.

I concur that is a telephone magneto, used to generate the ringing current on old manual exchange sytems or simple point to point systems.

Robert G8RPI.

I'd use a angle grinder (or toolpost grinder) with a ttin cutting disk to take the teeth off. Tidy up with grinding disk before turning to size.
This could be done on the lathe or rotary table (with protection fom gringing dust) or a jury rig on an old wheel hub and grinder holder. The gear teeth may well be hardened.

Robert G8RPI.

I don't think two screws are automatically better and you would have to use toothed belts (or encoders and feedback if you are of an electronic bent) to keep them syncronised.. One thing to consider is rollers or bearings of some sort on the outside faces of the frame. unless the weight is exactly centered the moving part will try to tilt sideways and as there are just flat plate it will lock up. The don't have to take the same load as the main rollers.

Robert G8RPI

Edited By Robert Atkinson 2 on 03/08/2019 15:36:23

For that application look at the track rollers I linked to in my earlier post

https://www.bearingboys.co.uk/SupportYoke-Track-Roller--1724-c

I also think you need two back braces either wire, rod or tube, one on each side to stop the frame twisting.
While I know Remap provide liability insurance, how do they deal with CE marking? As a powered lift for human this arguable comes under a whole raft of legislation. I'm not saying don't do it, just curious.

Robert G8RPI.

If you are literally using the outer of a drawn cup needle roller bearing on a flat surface like a tyre you will have trouble. The walls are not designed to be run un-supported. Running them un-supported will either roll the outers oversize or cause them to fatigue and breakup depending on the material and hardness. Have you considered using bearings with machined rings or even better a track type bearing?

**LINK**

You might get away with it at light loads but 100kg is not light.

Robert G8RPI.

Have you actually investigated the size of the motor in the tug? I looked at a baggage tug some years ago for a possible full size electric vehicle project. It was huge and very heavy for it's output. The tug was up for grabs and literally 1/4 of a mile away on the same industrial estate as my work but I still passed on it.

Robert G8RPI.

Hi,

The issue is present on two different radios on different bands but only in one of two locations. The oddity is that it's the location remote from the VFD that has the problem. see my earlier posts.

Robert G8RPI.

They start at £4 (plus VAT) from Farnell

**LINK**

I've used the Kellan ones for years. Mostly to clean copper clad circuit board material.

Postage free if you make the order up to £30 and they sell a wide range of products from tools to consumables as well as electronics. You don't need an account, just a credit card.

Robert G8RPI.

I use Kapton / Polyimide tape with silicone adhesive for this type of job. One possible issue for you is that while transparent it has an amber/copper/gold colour

example

https://uk.farnell.com/multicomp/mc001818/tape-polyimide-film-25mm-x-33m/dp/2770437?st=kapton%20tape

Robert G8RPI.

Hi ,

The Ideal solution is a two stage block filter like this

uk.farnell.com/corcom-te-connectivity/3eq1/filter-3a-1-phase/dp/9586210

But they are not cheap .As Geoff suggests a IEC mains input connector with built in filter is a lower cost ooption. It also has lower perfomance but one like this

uk.farnell.com/epcos/b84771m0006a000/filter-inlet-iec-medical-6a-250v/dp/2317950 should cure your problem and provide a handy inlet connection.

I could dig out a used filter if you don't want to order one.
Is your VFD in any kind of enclosure?

Robert G8RPI.

Hi Ron,

What is the full model number of your CUB VFD? With that information I can recommend a suitable EMI filter.

The manual can be downloaded here https://inverterdrive.com/file/IMO-Jaguar-Cub-Manual

Robert G8RPI.

It is likely differential mode conducted interference from the VFD causing the issue. You should fit a suitable filter on the inlet. Most VFD instructions say one is required.
The current from differential interference flows in opposite directions on the two conductors.(Live and neutral). Where these are close together and physically balanced the fields cancel and no signal is radiated. This is likely the case near the VFD hence no interference near it. The house wiring on the other hand is less likely to be balanced especially lighting wiring. Un-balanced or separated conductors act as an antenna so when the currents reach the house wiring they radiate and cause interference.

All VFDs should be in a swarf and splash proof (at least IP34, preferably IP 45 or better) earthed metal box with appropriate mains switching, fuse, filter, ventilation or space for cooling and cable glands or connectors.

Robert G8RPI.

Google DIN 49 491 and see if a local supplier comes up.

EDIT Don't forget to give those pins a good clean before you plug you new connector in even for a trial.

Robert G8RPI.

Edited By Robert Atkinson 2 on 30/07/2019 12:33:27

This will run from an inverter but as old mart says you will need a dedicated feed. Not necessarily it's own consumer unit (CU) but certainly it own 25 or 32A circuit breaker in an existing CU and either 4mm2 (possibly 6mm2) twin and earth cable or if the workshop is outside 2.5mm steel wire armoured cable (possibly 4mm 2 if a long run) to a dedicated isolator and box for the inverter.
If you have other large electric loads like a cooker, shower, water heater etc that may be on at the same time you need to look at the supply capability. Many houses only have a 60 amp main fuse so a bit of heavy turning while SWMBO is showering while dinner cooks and the washing machine is on might exceed the capacity of the supply.

Robert G8RPI

A weird one is "Smartwater" from Coke where they distil perfectly good British spring water and then add Calcium Chloride, Magnesium Chloride and Potassium Bicarbonate back in! For starts if you are going to distil it why use spring water rather than tap water?

Bizarrely (to me anyway) people buy the stuff. I guess they are the same people who pay 3 to 4 times as much for the same painkiller or other medication with a fancy name and packet as the generic version. I just checked Boots website Neurofen 200mg tablets 14p each, generic 3p each. Neurofen is more than 4.5 times the price).

A bigger risk with distilled or DI water is mixing containers. Many years ago I worked for a small airline on an island and we did frequent compressor washes of the turboprop engines but were still having sulphidation issues on the blades. The washes used distilled water bought in large containers from a local supplier. Turned out that their main market was the motor trade and they were not fussy about cross contamination between battery acid and water.
I found out when asked to pick up an order from Boots as I was going into town. My little car was totally filled with 2l bottles of distilled water. When I found out what was going on I suggested an Elgastat deioniser. It took a bit of convincing (DI could strip ions from the blades but as we added a detergent to the wash this was moot) but they changed to DI and had no further issues. It also cured the high failure rate we were getting with the "wet" NICAD aircraft batteries.

Robert G8RPI.

Typically they are fishing for you to make a personal injury claim, either genuine (you hadn't bothered), exaggerated or plain false. A number of UK police forces got told off a few years ago for providing accident data to this sort of company. They may also be fishing for details to make a fraudulent claim.
SWMBO say the other side of this a few years ago. She scraped the side of a parked car while avoiding a speeding "white van" overtaking a cyclist in a narrow street. No one around so took details of car. and photos (I came out to make sure she was OK), left a note, called the police and our insurers. Owner rang to thank us for leaving note (he had been hit before judging by the two other colours of paint transfer. Insurance paid for both cars to be repaired, all done. Over a year later she got a call form "the insurance company" about the accident, thought it was a scam so told them to write to her. Letter arrived saying that as we had admitted liability for the accident they were going to pay the injury claim. No real references. So called them and it turns out a personal injury claim had been made for her hitting a empty car. Rightly they would not provide details but we stated categorically that there was no one in the car, sent photos (from two phones) and the police reference number. A few weeks later we got a letter saying they had questioned the claim and the claimants solicitor had withdrawn the claim without comment. The insurance company thanked us for our help. I don't know if it was the car owner or a third party who maid the claim of if any action was taken against them.

If we had not bothered to tell the insurance company they would have got away with it.

Robert G8RPI.

Fatal Acetone accident safety video

https://www.youtube.com/watch?v=9DP5l9yYt-g

Yes, pure methanol burns with a flame that is invisible in daylight. There is a video taken form a helicopter out there of a crashed tanker truck be sprayed with water by firefighters, suddnely the firefighters fall over for no apparent reason. The video then switches to the thermal camera image which shows a huge fireball.
MEK and Toluene are other solvents with fire hazards. Thy can be ignited by static generated by cleaning with a cloth.

Robert G8RPI.