Member postings for Les Jones 1

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

Hi Phil, Many of these NVR switches do not even have a separate maintainer contact. If It turns out that the only fault is the maintainer contact (2 to 6) then I am going to suggest linking 1 to 4. I think it is unlikely that the 2 to 6 contact AND the coil have both failed.

Les.

I am even more confused. Are you using an analogue or a digital meter and if it is digital is it auto ranging on the resistance setting ? I don't understand the 1 reading. (You don't say if this is 1 ohm, 1 K ohm or 1 Meg ohm.) Normally on a resistance range with the test probes not conneted to anything or each other the meter would display something like ol to indicate the resistance between the probes is higher than the meter is capable of reading. If the probes are shorted together it would read 0.00. (If it is set to al low resistance range it can give a small reading of probably les than 1 ohm which will be the resistance of the test leads.) Does your meter behave this way ?

Note to Phil. This type of NVR switch does not have a normal start an stop button. The start button just manually pushes the solenoid to the closed position and the stop button just forces the solenoid to the open position.

Les.

Edited By Les Jones 1 on 27/08/2020 15:00:05

I assume that when you say "nothing" you mean infinite resistance. If not what do you mean ?

What was the resistance reading between 1 and 5 ? (I don't understand what you mean by "thing".)

Les.

Edited By Les Jones 1 on 26/08/2020 17:43:33

If the fault is the contact set 2 to 6 then it should be possible to get it to work by a small change to the way it is wired.

Les.

This is my interpretation of the wiring.

Contacts 3 to 7 and 4 to 8 must be working as the motor runs while the start button is held in, (The start button just pushes the solenoid in,)
The fault must be the coil is open circuit or contact set 2 to 6 not closing. With the mains cable unplugged first measure the resistance between 1 1 and 5. You should get a reading of a few hundred ohms. Then connect your meter to 2 and 6, You should get a very high (Probably over range reading.) Then push the solenoid armature in. The reading should drop to close to zero ohms. Report the result of these tests.

Les.

There is probably a centrifugal switch inside the motor that disconnects the start winding when the motor is up to speed. Probably an NVR switch such as this can be used. (There are also many advertised on ebay.)

Les.

It sounds like either the coil on the coil on the contactor is open circuit or the maintainer contact is not holding the coil in after the start button has been pressed. The stop button will be a normally close push button and if that was open circuit it would also prevent the the coil from holding the contactor in. I assume the rectangular thing with 8 connections is the combined contactor and start and stop buttons. you have not shown which connections go to the coil or the layout of the contact sets. I have tried to find a picture of your contactor assembly but failed. Some pictures of the contactor may help in understanding the contact and coil connections. I think a standard NVR switch can be made to work.

Les.

Tim, You are going to have to provide more information on the "LED". A single actual LED (I am assuming it is a white LED as different coloured LEDs have different forward voltages.) would have a voltage of between 3.0 and 3.6 volts across it when driven with it's rated current. As you are calling it a 12 volt LED it must contain something to limit the current and it may consist of more than one actual LED. Until we know more about the "LED" we can't work out a possible reason for it failing.

Les.

The TNY264 is also a 7 pin low power switch mode regulator chip. It would be nice to know the part number of the chip on the board as the picture is not good enough to read it.

Les.

This is a link to the manual for the CL300M which contains a wiring diagram but not a schematic of the board. (Which I have not been able to find.)

Les.