Member postings for Mike Poole

Safari works for me, running IOS 15.3

I can view all issues from No.1. Using my iPad but not with my PC running Win10

Mike

Edited By Mike Poole on 31/01/2022 17:24:08

I may have made an assumption that the NT box EStop will just stop the motor but the additional EStop would stop the CNC as well. In the event of a crisis with the CNC you will have to remember to hit the extra EStop as the NT button will not stop the CNC. As it is likely you will be the only user in your own workshop then the functionality of the 2 buttons will be known but in an industrial situation you would expect hitting the nearest EStop to stop everything.

A VFD normally behaves as though it has an NVR in it so in the event of a power failure or hitting the EStop it will not restart when power is restored, some VFDs have a parameter that will restart the motor when power is restored but this is usually used where no danger will arise from an automatic restart, applications like a pump in a remote unmanned location where it would be desirable to have the pump restart as soon as power is restored. Obviously restarting a manually operated machine unexpectedly could be dangerous.

Mike

A bit surprising that Honda can’t supply those parts now, I assume they can’t as Stefan is batch making them. Our tool room sometimes did contract work and one job was an impeller but rather larger than a CX 500 one. It was around 3ft in diameter and about a foot deep. They decided to machine it on a Marwin Numerical controlled milling machine which had an Olivetti NC which ran from 8 hole punched paper tape. The Marwin was getting a bit long in the tooth and not a super reliable machine, the axes were all hydraulic rams but the table had a recirculating ball screw with hydraulic motor, the control for each axis hydraulics was a Moog valve. The Marwin was on its best behaviour and ran fautlessly for the 6 weeks that the machining took.

Mike

They say Coleman’s mustard made their fortune from the mustard people throw away, I suspect the manufacturers of paint have made a fortune from the paint left over from a job that ends up never getting used. I have a bin full of paint tins with varying amount of paint after clearing my mothers property, try finding somewhere to dispose of them responsibly.

Mike

The shellac we used sounds vey like the stuff you have Clive, we baked all our motors to harden the shellac and after baking it had set quite hard. I am not sure what the bake temperature was. I am not so sure as Clive that the connection of the coils doesn’t matter but if if doesn’t run sweetly then swap each winding in turn until it runs best. Motors can run at quite a high temperature without stress, in fact we have had to strip and bake motors that have been flooded to dry them out. Modern motors can run happily at temperatures that would be very uncomfortable to put your hand on for any time but to reach those temperatures they need to run at full load for extended periods. It looks like the star point extraction has gone well so good luck with the final assembly and testing.

Mike

Killing the supply to the VFD via a NVR is an effective EStop. It would be best to not use the EStop for stopping the motor unless in an emergency but operating the EStop with the is drive stationary is the same as turning it off. If you are going to work on the drive train then pulling the plug is the ultimate safety device but if the EStop button latches then an accidental restart would be most unlikely as it would require the button to be released the NVR reset and the drive start button to be pressed. Having two EStop buttons that do different things is not ideal but if you can live with the button on the NewtonTesla box only stopping the motor then the NVR can be wired to stop the CNC and the motor. Personally I would invalidate the warranty and open the Newton Tesla panel but I understand the downside of doing this.

Mike

The best chips I have ever had were in a pub near Mablethorpe, we saw the spuds being delivered, no ready prepped chilled chips or frozen there.

Mike

A friend had to climb into a tight corner to do some gas welding, he posted his mate to stand by and turn the bottles off if anything went wrong, I can’t remember what happened but the hoses finished up on fire and the mate panicked and legged it. Don had to extricate himself and turn the bottles off, he was not happy with the mate.

Mike

Mitering coving was my problem but now I seem to have it cracked, my first job involved a chimney breast which requires three pieces with the correct ends and the correct length, that was probably the peak of my learning curve and scrap production.

Mike

I think the purpose of the shellac was to stabilise the windings so that the wires could not fret and compromise the insulation, these days it seems to be a liquid epoxy. We used to use a flat cotton tape like the motor in the pictures and the shellac would be absorbed to deny any possibility of moisture being absorbed. We would use an off cut of the winding wire as a needle to thread the tape through the windings, bent to form a blunt end to avoid damaging the windings. The interconnections were made by twisting the ends and flashing them with an oxy-acetylene torch to fuse the connection into a neat ball. To solder the ends to the tails it is easy to burn the insulating varnish off the wire and scrape clean, just scraping is not so easy as the coating used Is extremely tough, if you use a flame use a small one and keep an eye on where you point it.

Mike

Well Duncan, conniptions is a new word for me, everyday is a school day.

Mike

My bench is seldom seen so the colour tends not to matter too much, it is actually a piece of worktop that is a sort of oatmeal colour. The colour was chosen because it was the cheapest 38mm top in the shop. The vice is mounted on a 8mm thick steel plate and bolted through to the steel frame below, I always mount the vice over a leg for maximum support. When the top becomes too tatty it will get a layer of hardboard and be varnished.

Mike

It may have a retaining screw for left hand running, open the jaws wide and check for a screw into the end of the drive shaft.

Mike

My eldest son lives in Bristol and has done since he went to university there, they keep moving the goalposts so as soon as you think you know where you are going they change it round. It may not be a problem for much longer as my diesel cars are probably going to be banned so may have to bus or train to visit. I collected a parking ticket once when moving son and girlfriend to new digs, the traffic warden was most apologetic as he had given us as much time as he could and had just written the ticket when we returned, he advised us to appeal and the council cancelled the ticket. My fault really for developing a removal man’s thirst and grabbing a quick cuppa instead of parking the car properly. The motorbike killers used to be Volvo drivers, they seemed utterly oblivious to motorcycles and they rarely disappointed when pulling out of side roads to test your brakes, BMW and Audi drivers now seem to want the top spot for bike killers now. I have joined the BMW drivers now and I hope I still drive courteously and considerately, the car has not changed me I hope.

Mike

With a dip tank close by it is no trouble to dip before things get too hot, although HSS should not lose its temper easily I am convinced that the edge of a tool that has been overheated when grinding is not a durable as one that has been kept cool. Tools with thin sections are very easy to overheat and care should be taken to avoid overheating by keeping things cool.

Mike

A controlled stop which is when you just want to stop the motor with the normal stop button which will bring the motor to a stop under the control of the VFD and can be programmed to be a very fast stop. Perversely an emergency stop will be uncontrolled and probably slower than a normal stop, many VFDs now have a safe torque off feature which can inhibit the drive to the output stage thus being a safety stop, the other option is to kill the supply to the VFD which results again in a coast to stop. An emergency stop must be able to halt the drive in the event of the VFD control failing in such a way that it is unable to halt the motor, safe torque off is a safety circuit that should fail safe if it fails itself or will effect a stop when requested. Wiring a mushroom estop button to the motor off control is not an emergency stop.

Mike

Edited By Mike Poole on 25/01/2022 14:27:07

I was a regular cyclist from the age of eleven until my late twenties and a motorcyclist until I was sixty. The cycle lanes that are now fashionable along the side of a road encourages cyclists to undertake stationary vehicles which as you have discovered is fraught with danger. I would be reluctant to use lanes that put me at risk in this way, cycling to school from eleven through city traffic I learned to avoid risk, I bet the idiot who opened the door on you never felt a thing even though they are in the wrong. Being hurt and in the right is not where you want to be so I regard those sort of lanes as a trap.Before the appearance of these traps the traffic would be close to the kerb and so like all the other traffic I would wait in line and be clearly visible to the car behind me and of no concern to the one in front. There is no need to be at the front of the queue unless you are one of the many cyclists who ignore traffic lights so just wait in the queue in safety. Pavements were for pedestrians and I feel these shared spaces we now have even if a painted line is supposed to separate us are just dangerous. The passing distance that is recommended is just not achievable in many situations and how can it be achieved with oncoming traffic on a country lane? The requirement to pass wide must be to allow for avoiding a wobbling or crashing cyclist but they can still wobble or crash into oncoming vehicles and do. I long ago decided that everyone else on the road was an idiot so you have to look after yourself and ride or drive defensively, so far it is working well and the idiots certainly keep coming.

Mike

If a cyclist gets hit by a car door they must be natural born stupid, if they cycle close enough for a door to to hit them then it should not be a surprise when it eventually happens.

Mike

Although the possibility of disconnecting is built into a smart meter it would only be used in a crisis or to disconnect for non payment after a safeguarding process. Suppliers are in the business of supply so disconnection is not in their interest. The load sharing during the 3 day week was a very blunt instrument that shut everything down in a chosen area, some process could be used to keep essential services and vulnerable customers supplies uninterrupted if we ever finish up with a shortage of power, we seem to be running very close to the edge at the moment so it might only take a few unfortunate events to put us in trouble.

Mike