Member postings for Les Jones 1

If you know someone with a small EDM (Electrical discharge machine.) that would probably work.

Les.

Edited By Les Jones 1 on 24/10/2020 11:46:54

There was an article in issue 156 (Autumn 2009) of MEW on page 15 about using "O" rings. I don't know if that is the one you are looking for.

Les.

Duplicate post.

Les.

Edited By Les Jones 1 on 16/10/2020 20:24:40

I too can't see how changing the the NVR switch can effect the problem.

Les.

We have now confirmed what I suspected in my post on 01/09/20. It has taken 41 days to confirm what would have taken a few seconds if I had been standing next to the band saw.
This is how I suggest connecting thing together.

It will behave slightly differently to the way it was connected in your original diagram, In your original diagram the micro switch was switching the full motor current which was more than it was rated for. It is now only switching the current taken by the coil in the NVR switch. This means that when the cover is open the motor will run while the green button is held pressed. The way it was connected the motor could not be made to run with the cover open.
It is now wired in a similar manner to the schematic in the manual. If you don't want to fit the lamp just don't connect it. (It will work without it.) Whatever physical changes you make to fit the new NVR switch the micro switch MUST be held closed by the left hand cover while it is closed.

Les.

This is still not the picture I asked for. From the second picture picture in your post at 12:46 on 11/10/20 it looks like the black plastic control box is mounted on the die cast right hand side of the machine and it looks like there is a hole in the hinged left hand cover of the machine that allows access to the red and green buttons, the hole for the key and the indicator light. It looks like the hole in the left hand cover does not go down as far as the plunger on the micro switch. I want to see the INSIDE OF THE LEFT HAND COVER so I can see if there is something on the INSIDE of the cover that presses against the plunger of the micro switch when the LEFT HAND COVER IS CLOSED. This would then explain the purpose of the micro switch.

Les.

It is the inside of the panel on the left hand side of the machine that I want the picture of. I think this is hinged at the back of the machine and opens to access the blade and drive rollers.

Les.

I have a suspicion that the cover on the left hand side of the machine covers the lower part of the original switch assembly. Am I correct ? Can you post a picture of the INSIDE of this cover showing area around the hole is for the original switch covering about 4 inches around this hole. I think there will be something on the inside of the cover that presses on the micro switch when the cover is closed. This is why I want to see the picture.

Les.

It looks like the motor is probably OK. Even if your mutlimeter has an AC current range it will probably be 10 amps maximum and the motor will take more than this when starting. This test was to ensure that the motor did not take a VERY large current that could destroy the new NVR switch. As it did not blow the fuse in the plug it is unlikely to damage the new NVR switch. We now just need to establish the exact purpose of the thing that you called a trip and DeWalt call a micro switch. It is a pity that you have disposed of the original item before we could establish if it was a thermal overload trip or just a NO micro switch.

Les.

I agree with Dave's comments. I am not going to draw a wiring diagram for you until we sort out the function of the thing you called a trip and DeWalt call a micro switch. I suspect that the item to the left of the KJD18 (NVR switch) is a emergency stop button. Can you post a picture of the front of the panel that it is on and also the side of this item so we can read the ratings ? (This is so I can decide between wiring it to break the full load or just the feed to the coil on the NVR switch.) Can you also measure the resistance between the connections second new micro switch both with it pressed and with it not pressed ? Can you also post a picture of where this switch is mounted so we can see if it is some kind of safety interlock ?

This is how to connect the motor directly to the mains to confirm that it is not drawing a very high current as I suggested in my post on September 10th. (This is to avoid damaging the new NVR switch if the original fault was caused by the motor.)

Les.

Hi John,
I have emailed you a copy of the manual for the Teco VFD that I use. (1HP). I hope this is of some use.

Les.

Edited By Les Jones 1 on 21/09/2020 18:12:20

As you can read the floppy on your laptop try making a copy onto a new floppy disk. From memory the command at the command line prompt is something like diskcopy A: A:

If the problem is a marginal alignment problem that might just work. Using a head cleaning disk in the suspect drive may also solve the problem.

Les

Hi Marsh,
You still seem to be confused. The KJD18 IS an NVR. (No volt release switch. This is to prevent the saw from starting when the mains is restored after an interruption to the mains supply.) The A1 terminal is one end of the holding (Or maintainer.) coil. This coil is fed from the NVR's output to hold it closed after the start button has been pressed and released. The thing you have labelled "NVR" I think is the item that there is confusion about, (The thing that you called a trip.) (Which we all assumed was a thermal overload to protect the motor but seems to be called a micro switch by DeWalt.) To avoid risking destroying the new NVR if it was the motor that caused the original fault I suggest Connecting the motor directly to the mains with the belt removed from the speed change pulleys and monitoring the current it is taking. This is relying on the 13 amp fuse in the plug to blow if the motor is taking a much higher current than it should. You need to test the second new thing that you called a trip with your meter to see if it behaves like a thermal cut out or a NO micro switch. You also need to show a picture of the diagram on your KJD18 as the connection numbering seems to vary on information I have found online.

Les.

When you receive the second new micro switch test it with your meter BEFORE fitting it to the saw to see if the results are the same as you reported in your post at 12:20 on 01/09/20 for the first new switch. Do you have a way to measure the current taken by the motor ? I expect the running current to be about 5 amps but the starting current will probably be over 20 amps. (It would probable draw the starting current for less than a second.) If you do then I suggest connecting the motor directly to the mains with a fuse in the circuit. (If you are in the UK then the 13 am fuse in a 13 amp plug will serve the purpose.) The reason for this is that I suspect the motor may be drawing too much current which has damaged the NVR or the original trip switch. In one of your posts you said that the resistance across the capacitor terminals was 2.66 ohms. This is actually the resistance of the two motor windings in series. This value seems low for that size motor.

Les.

With that micro switch connected as in the diagram in your first post or connected as in the drawing in the manual the motor can't run unless that switch is closed. (For it to be closed it must be pressed from the results of your test in your post at 12:20 on Sept 01.) Can you confirm that your diagram in your first post shows correctly hoe the micro switch is connected ? The KJD22 NVR that you showed in a previous post and the 4 pin version are available from this supplier.
**LINK**

Either version could be used with your band saw. According to the manual versions of your band saw for some countries do not have the micro switch fitted. This is probably to comply with the regulations for different countries.

Les.

From your test on the switch that you call a trip switch and DeWalt calls a safety switch it just seems to be a normally open push button switch. The way you show it connected in your first post it must be in the pressed position for the saw to work. Can you post a picture of the original switch that was saw when it failed showing any printing on it. From the description safety switch I am wondering if it could be an interlock switch to ensure the cover is closed for the saw to work. If this switch is intended to be pressed manually is the a label next to it ?
The KJD22 NVR switch should work but it does not have the key function.

Les.

I have now found the manual for this saw here
**LINK**

It includes a schematic but does not seem to be quite the same as I suspected. It does not show the item that Marsh calls a "Trip switch" which he shows directly in series with the input live feed. I had assumed that this was a thermal overload trip switch. The schematic does show a safety micro switch which only breaks the feed to the contactor coil. The manual also shows that there is a safety key which has to be inserted to start the saw. I am now wondering if the thing that Marsh calls a "trip switch" is this safety micro switch.

Marsh, Can you confirm that your saw does NOT have the key that is shown in the manual ? With the "trip switch" not connected can you measure the resistance between it's contacts with it not pressed and also with it pressed.

Les.

Hi Marsh,
It looks like the "1" reading is your meters way of indicating over range. (Open circuit.) I now have confidence in the resistance readings in your last post. They seem to indicate that the schematic I drew is wrong. If it was correct then without the solenoid pressed in 4 to 8 should be open circuit (Your meter reading "1".) and with the solenoid pressed in it should have read 0 ohms.Can you confirm that it was the overload trip button that you had to hold pressed to get the motor to run after the initial fault ? (NOT the start button as originally thought.) Have you checked that the motor is free to turn by hand ? What is the mains voltage in your country ? (I am thinking that if it is 110 volts Then a overload trip for the 240 volt version may have been supplied. This would be about half the current rating required for the one for 110 volts. You do not need to worry about about the capacitor. It is wired the same way as it would have been wired if it was strapped to the motor. The NVR switch I linhed to is a 240 volt version but you may need a 110 volt version.

Les.

I have just been reading through the thread again. I had misread the first post and thought that the motor ran when the start button was held pressed but you actually said when the TRIP SWITCH was held pressed. All I have said so far is not relevant. If you have to keep the trip switch pressed in then the motor is taking too much current or you have been supplied with the wrong current rating of trip switch. (You should never hold a trip switch in as it is designed to remove the supply id the load is taking too much current.) Sorry for my error in reading your first post.

Les.

Hi Phil,
I agree that it looks like the spring clip holds the contact assembly to the solenoid part. I did think about suggesting trying to remove the contact assembly but decided that springs and other bits might fall out. I have just seen Emgee's post (I opened another session to look at the NVR pictures again to avoid loosing what I had typed.) I agree that my schematic may not be correct. This is my reasoning. What I assume to be contacts 3 to 7 and 4 to 8 seem sensible to provide double pole switching to the motor. As the indicator light is connected to 1 and 5 it seems likely that the coil is connected between those two points. This left 2 and 6 which seem to be wired as the maintainer contact. I am trying to understand Marischal's readings. In his post at 11:12 on the 26th he says the reading between 1 and 5 is "thing" and the reading between 2 and 6 is "nothing". I assumed by nothing he meant open circuit but he has not yet told me what he means bu "thing". In his post at 18:22 on the 26th he says the meter stayed at "1" I initially thought he had a reading of 1 ohm (Or 1K or 1M) but I am now wondering if just 1 (As opposed to 1.00) could mean overrange on his meter. I am waiting for clarification on this.

Les.

Edited By Les Jones 1 on 29/08/2020 18:11:45