Chipmaster motor wiring

[colin hamiltonParticipant @colinhamilton16803]

Just bought myself a Chipmaster. I need to run it via a VFD. My (basic) understanding g is to use the VFD I've bought the motor needs to be in the delta configuration. All of my searches to date of motor windings all have very mucky labelled square connection boxes with straight connectors

I pulled off the cover on my starter and the connections dont seemed to be labelled (it's very akward to see due to the position of the motor below the variator) and its round with a couple of very nice curved links. For the life of me I cannot reconcile this with the all the vids I e watched. Can anyone help? I took some photos but haven't worked out how to upload them yet!

[colin hamiltonParticipant @colinhamilton16803]

[larry phelan 1Participant @larryphelan1]

I dont think it,s the starter you should be looking at. Perhaps you should check the position of the links in the motor terminal box ? One way for star, other way for delta.

[Mike HurleyParticipant @mikehurley60381]

Colin, just select FORUMS from the top of these pages and select Website FAQ's – all you need to know about posting photos and other useful stuff

regards

[noel shelleyParticipant @noelshelley55608]

Hi Colin, Do you not have the wiring diagrams for the VFD ? You do not need a starter for a VFD, it should be set up for the motor being used. You need a delta form – you should have 6 terminals that must be linked in the correct order. some motors CAN NOT be configured to delta, star point being inside the windings. The data plate on the motor will show 2 voltages IF it can be set to delta 220V and 380V or there abouts. The starter may well have 400V coils so conversion may be a little more involved. Whilst many go for a VFD – Boxford or myford it's fine, for industrial machines you may be better off with a converter that runs 415v , Transwave Etc. Good luck Noel.

Edited By noel shelley on 25/08/2021 10:09:55

[DC31kParticipant @dc31k]

Posted by larry phelan 1 on 25/08/2021 08:39:15:

I don't think it's the starter you should be looking at.

I think if you read his post with rather less of a pedantic eye, you will see that his use of 'starter' is a slip of the keyboard.

Where he says, "(it's very awkward to see due to the position of the motor below the variator) and it's round with a couple of very nice curved links", he is indeed talking of the connection box on the motor itself.

The motor on the Chipmaster is of an old style that uses a round terminal block rather than the more modern rectangular one that is shown in the pictures he has seen.

The form factor is not relevant. It is just a six wire terminal block, currently wired in star. All coil ends are brought out to the terminal block so delta is not a problem.

See also:

http://wanderingaxeman.blogspot.com/2013/03/colchester-chipmaster-oils-instruction.html

[colin hamiltonParticipant @colinhamilton16803]

I'm loving this forum already. Lots of good information. Larry has hit the nail on the head my poor english! Yes iam talking about the motor connection box. I have sat and started at if for ages and have satisfied my self that it is wired in star. My problem is because of the apparent lack of labels and the fact that the terminal block is round I'm struggling to identify the matching windings to reconfigure to delta. Thanks to mike I have attached some photos. Any advice in identifying the appropiated connections would be appreciated. Appologies for the quality of the photos but it's a nightmare with the motor installed

[colin hamiltonParticipant @colinhamilton16803]

Blimey I've just zoomed in on my own photo. Is that small labels on the wires?

[DC31kParticipant @dc31k]

The wires are labelled. The motor is connected in star. Red, blue and yellow are the three incoming phases from the control box. They connect to one end of each of the three motor coils. The other end of the motor coils are under the curved link bars.

You can easily rearrange it to delta. You will end up with three wires on three terminals: one incoming phase wire, the 'beginning' of a coil and the 'end' of the next coil. The three unused terminals can be used to store the now unnecessary link bars.

[noel shelleyParticipant @noelshelley55608]

AS DC3, OR There will be no unused terminals and you will link the end of one coil to the start of the next along with a phase, rather than risk damaging the old insulation by moving them around. Good Luck Noel

[colin hamiltonParticipant @colinhamilton16803]

Thanks DC3 and Noel.

I wasn't sure about moving the winding wires so I made up some short jumper cables and reconfigured (I think) to delta. Does it look ok to you?

[DC31kParticipant @dc31k]

Looks good.

If you want extra peace of mind, you could remove the jumper wires and measure the resistance of one coil (or all three individually and average). Add back the jumper wires but not the phase wires and measure the three phase-to-phase resistances. They should all be the same and you can calculate the value relative to one coil.

[noel shelleyParticipant @noelshelley55608]

Looks OK to me as DC3 has said check the resistances just to be sure. Good luck Noel.

[colin hamiltonParticipant @colinhamilton16803]

Thanks for the advice regarding the resistances and they are all good. I do have other issues. When I first wired it all up I was getting a short circuit fault showing on the VFD. There is all sorts of things in the lathes electrical junction box. I jumped past all of this and wired the VFD direct to the motor and it runs fine. I think some of my settings in the VFD are wrong. I dont have any way of measuring the motor speed but I think at 50 hz (on the RFD) it's way over speed. It seems happy at around a max of 31 hz.

[John HaineParticipant @johnhaine32865]

In what way is it unhappy at 50 hz? The only vfd setting that can affect the speed is frequency and the plate shows this as a 50 hz motor.

[John HaineParticipant @johnhaine32865]

Another thought – it's just possible that one of the windings might be "backwards" relative to the other two. It's all to do with the mutual inductances between the windings, which need to all be in the same sense. Are the ends of the windings clearly differentiated (e.g. by labels)? The END of one needs to be connected to the START of the next. If one is incorrect the motor apparently can run "lumpy" – contrary to what is sometimes said it does NOT reverse the direction.

[john fletcher 1Participant @johnfletcher1]

To John Haine, A friend of mine altered his motor prior to wiring in an invert and he had a "backward" connected winding. I sorted the problem by reconnecting each, one at a time, can be tricky never the less. When one end is incorrectly connected you are not forming a triangle, not sure of the title of the new shape. . As always there is a way out. You will ned an analogue multi meter or a low voltage DC volt meter ( 15 or less) will be OK. The reason for the Analogue type is because you will be looking for a quick flick or deflection of the needle + or – and most digital don't show that easily. In the past I've used an AVO set on 10 volts DC, start high and work down to the 3 volt range rather than damage a meter. Using a crocodile clips connected to the meter to leads, to say V1 and V2, doesn't matter which of the three pair you start testing. Using a 12 volt car battery or any 12 volt DC supply connect the Negative lead of the battery to W1 motor lead, and then very quickly dab Positive lead to W2 us should get a small kick / deflection on the meter. If the needle is attempting to go in the Negative direction exchange the labelling on W1 and W2. Conversely if the meter reading is in the + direction you got it right first time. Now go to the other two windings and do the same to them. I think I've got it all correct. John

[John HaineParticipant @johnhaine32865]

Indeed John, that is the method, best addressed to Colin though.

[colin hamiltonParticipant @colinhamilton16803]

Thanks everyone. My windings are labelled so I'm ok with their orientation. I found a formula that relates the number of poles to the motor speed and frequency (both of which are listed on the motor plate). It turns out I've got a 4 pole motor and the VFD was defaulting on 2. Motor is running nicely now at 50Hz.

I fell like I'm getting there slowly. I just need how to learn to fault find on all the stuff between the motor and the VFD!!

[Les Jones 1Participant @lesjones1]

There should be nothing other than a length of 4 core (3 phases + earth.) screened cable between the VFD and motor. There should be no contactors or switches between them.

Les.

[colin hamiltonParticipant @colinhamilton16803]

Les, what's the issues? I was hoping to use the on/off/ reverse switch on the lathe so I could have the VFD out the way on the wall behind

[Les Jones 1Participant @lesjones1]

It is not recommended to do any switching on the output of most VFDs. I suggest that you check with the manual for the VFD that you have. You normally have the forward ,reverse and stop controls together with the speed control potentiometer mounted in a convenient position away from the VFD. The wiring between the controls and the VFD is only low voltage and current so thin multicore wire is used. It is probably possible use the old forward/reverse/stop controls connected to the control inputs of the VFD. using the old controls in this way may give problems as sometimes the contacts oxidise when there is no cleaning action that occurs when switching high voltages.

Les.

[John HaineParticipant @johnhaine32865]

If you forget and open the switch between VFD and motor while running it can generate an inductive spike that destroys the output transistors. Much better to make a direct connection and do the switching and control on the control side of the VFD. For one thing you can usually set the VFD for a controlled accelerate/decelerate time – no need for a clutch.

It won't be so relevant on a lathe, but on a mill for tapping it's convenient to have the motor set for running slowly (say 10 Hz with a large belt reduction), then bring the tap down so it's just resting on the top of the hole, switch on in forward, run the tap to the desired depth then just switch from fwd to reverse. The VFD will happily bring the motor to a controlled stop then reverse with no drama. Try doing that with a normal reversing switch on the VFD output and it would definitely object!

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