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Member postings for Martin of Wick

Here is a list of all the postings Martin of Wick has made in our forums. Click on a thread name to jump to the thread.

Thread: VFD. XSY AT4 220v 1phase to 380v 3phase advice sort
23/05/2020 23:08:56

Hmmm....

just seen your latest post... will be most interesting to see if reducing your P74 75 parameters to manual values actually gives you back full frequency control on the external input - It would then be the exact opposite of what happened in my case! Go figure!

P67 is another parameter you may need to have regard to as it is often different from the one listed in the info sheet.

I didn't detect any voltage between device and mains earth when I set up

23/05/2020 22:56:39

On my AT4 version, after some head scratching, I found the earth was located on the outer left-most terminal of the of the left hand green block above the 220v power input on your picture above- it is marked PE in minute lettering obscured by the casing (WTF!....yeah I know! …. don't start.), but don't take my word for it, check to ensure there is connection to the cooling plate.

On my device, parameter 74 is 63500 and P75 is 4200 basically the span and offset values for the external control.

Originally I noted these values along with other obscure parameters prior to use of the device (and a bloody good job too) seeing they were different from the 'manual'. As a test I input the values quoted in the 'manual' that were about half the 'as supplied' values and had similar half F issues.

I then did a reset (bad mistake - don't ever be tempted to do one). The reset resulted in the same low values replaced in P74 and P75 (among a whole lot of other unwanted changes).

I suggest you check what P74 P75 contain. If the stored values appear to be about 31000 and 1100, you could try the higher values quoted above and see if that helps and experiment from there until you are getting the range of control that you want.

Above all take care, this thing is a pretty scary device to have floating around on the test bench.

 

 

Edited By Martin of Wick on 23/05/2020 23:14:06

Thread: vfd question
20/05/2020 17:29:11

John,

you can use either momentary or latching, depending on what parameters you program to the multifunction inputs P50 to 55.

The supplied 'manual' lists the switching types available, but has been so badly translated that the terms are meaningless in English and utterly unsatisfactory. Originally I worked out what they might be from the supplied description, but then experimented to prove the hypothesis.

See thread titled AT1 inverter 3 wire control, I think the very last post in that thread has a detailed description and practical descriptive use of the listed parameter functions (as determined by me on the examples that I have worked with). If you cant find it, let me know and I will PM you a copy.

Should at least get you going but you can always run a test setup to experiment with the switchgear of your choice to find what works best for your application.

Remember, AT1 multifunction inputs are all LOVO stuff so you don't really need expensive 600v /20A switchgear or to shell out Farnell/RS etc. Reasonable quality stuff from the usual eastern sources will do.

Thread: Warco WM16 and Chester 20V owners
27/04/2020 17:56:02

The answers for my WM16 in order of questions are:

Yes up to about 6mm in steel but you have to go slooow if you have any mechanical sympathy

In steels yes, but not in one hit - after roughing out, I generally do one side then t'other, never tried very small slots at one pass,' spect they would be oversize though.

Don't know - I expect it would be doable but slowly to respect the mechanical limitations of the mill

Yes

Nope

Not yet

Table too big, column too small, motor too noisy and no taper eject on the spindle not happy with slow heavy cuts.

The new fangled carbide tooling has been a boon for this mill and I have changed technique to suite - set RPM to maximum possible, shallow depth of cut, calculate a suitable lightish tooth load and twirl the handle to approximate the required feed. Basically treat as a manually operated high speed CNC mill hi speed lite cut repeated often until your arm gives up.  Much less shake rattle and roll.

 

 

 

 

Edited By Martin of Wick on 27/04/2020 18:01:03

Edited By Martin of Wick on 27/04/2020 18:04:01

Thread: Leaving filament in printer or not
14/04/2020 21:33:52

In the past, I used to leave the open spools (PLA) on the printer for months with a feeble attempt to cover/protect from sunlight with old box, paper bag etc.

However, recently noted two issues;

Where the filament run to the hotend had been exposed to sunlight, it had become brittle and snapped like cheap spaghetti, the stuff on the spool that had minimal protection was OK, I just determined the extent of the brittle section and cut it off.

When changing to a fresh spool of PLA of the same make, I noticed that the print made with the fresh stuff was notably better in overall quality than the old material that had been exposed for months.

Unless I intend to be using the printer on a daily basis, I now remove the spools, pack in airtight bag with silica gel and store out of the light.

It seems a bit of a faff at first, but you soon get the removal technique sorted. I did have a free demo reel of PLA that was completely shattered, couldn't even be unwound without disintegrating into tiny fragments. PLA from reputable suppliers has been generally fine unless abused as above.

Thread: vfd question
03/04/2020 11:40:15

Uh-hu...

you can cycle between rpm/ amp/ volt/ hz/ hrsrun/ temp by pressing the function/data key P62 just sets what comes on the display at startup.

Check how you have set P06 that sets the max Hz I would recommend no more than about 75Hz - that is 50% inc on design freqency. While it may be OK to run the motor at 2500 RPM, the torque will not be as expected, approx 50% relative to the higher speed.

The overspeed will be fine if you are wanting a speed boost for using a very small drill or some other low torque operation. However, if say using a large forstner in wood, there would be insufficient torque to maintain the set speed, so you may not gain much in that case, or by going to much higher frequencies (unless you are regularly using sub mm drill bits).

Looks like your display current is more accurate than some, which is good. I could have suggested another way to set trip current for real world practicalities. Get a large chunk of gnarly steel about 2 in thick and your largest drill (I assume 1/2- use an old bit you don't care about) set machine gearing for approx. RPM for material and start drilling like you don't give a **** while observing the indicated current, then set that or just above that as your trip current - as being defined by the nastiest job you are likely to do!

 

Edited By Martin of Wick on 03/04/2020 11:45:16

Edited By Martin of Wick on 03/04/2020 11:48:40

02/04/2020 21:38:23

A) In my limited experience of these simple devices, the display voltage and current is probably not a true indication of the actual RMS voltage and current taken by the motor. However, the indicated display is what the overload current setting will cut out at.

This makes setting a meaningful overload current cut out problematical. Ultimately it will depend on how bold you are or how much you think your motor will take. A reasonable quality induction motor is fairly tolerant, so here is what I would do as a start.

check current draw indicated at no load - say it was 2.0A the real current load should be closer to 1.1A divide 2/1.1=1.8 now say you will tolerate 1.5A for a short run overcurrent ( say 3 seconds set at parameter P24) then multiply that by 1.8 which will give you 2.7A as a possible overcurrent setting. If it was me, I would set it at 3, but be prepared to check the temperature rise in the motor if working it hard.

B) There is not enough information on how you have set up for your drilling operation. At half frequency, the power being delivered in your system is only about 110 watts. depending on how hard the steel is and how sharp your bit is and whether you are using the correct RPM, that may not be sufficient to maintain speed/Hz relationship so the VFD pulses open up delivering additional voltage and current until the trip is activated (or not, in which case the motor will potentially overheat if care is not taken).

In the first instance, leave the motor at the full frequency and set the pulley system to give somewhere in the region of 800 -1000 RPM for 1/4 in steel ( we are in the home workshop here, not industry). With a low power system, if you have to use the VFD to reduce spindle RPM by as much as 50%, to trim to an optimal setting then consider setting up with pulleys for a lower than optimum spindle speed, but use the full motor frequency (50 Hz). That way you will get the maximum power to the bit.

A VFD is not a substitute for the correct motor gearing.

I cant believe you are getting no torque at the 50% setting, but if you are, check that P02 is 110 and P03 is 25 with P04 P05 both zero.

Edited By Martin of Wick on 02/04/2020 21:39:19

Edited By Martin of Wick on 02/04/2020 22:07:15

02/04/2020 13:16:08

John, check carefully, is it one of these? If not, you will need to post the relevant part of your manual.

**LINK**

If so set P1 to P11 as per listed defaults for your voltage system (220v, I assume)

If P78 is listed as Main current overload on your instructions, set as 2000 for 1/3Hp motor to start with.

You do not need to repeat this for P79 to P85 unless you intend to use pre set operating conditions selected by a rotary switch.

P34 Main Rising Velocity can be set to your desired ramp start speed. At 10 Hz/s, run up to full speed at 50Hz will be about 5 secs (i.e. 50/10). For example, if you changed it to 25, run up to full speed will take about 2 sec.

Find a youtube video on how to use the shift key to rapidly select the digits you want to change rapidly with the arrow keys.

Thread: Brook Compton 1 phase motor KP6345
29/03/2020 09:59:24

Bruce,

I simply don't know. In most cases where I have replaced bearings, there have been two thin wavy washers. However, I have encountered an instance where there was only one, but whether by accident or design I couldn't say.

These spring/wavy washers can usually be obtained at modest cost from on line bearing factors.

Edited By Martin of Wick on 29/03/2020 10:00:12

28/03/2020 20:54:35

the wavy spring washer goes between the end housing and the bearing.

The dimpled steel washers were used with unshielded bearings and helped keep the grease on the bearing. They are fitted behind the bearing on the inner part of the shaft and retained by shaft shoulder or circlip (ie trapped between the shoulder and the bearing).

The dimples should be facing the bearing so the washer is slightly stood off the outer bearing shell slightly to avoid rubbing.

sequence is:

Housing- spring- bearing- washer- rotor+shaft- washer- bearing- spring- housing

Thread: DIY induction motor rewind
27/03/2020 11:23:44

Thanks to all those that helped, I will post here as a sort of build thread in future and put some photos in the album as I progress. Might be helpful for anyone else contemplating such madness.

The material for the job was approx. £30 as only about 800g copper was required when using vendors wire data and correct stripped diameter. Decided to have a go as a learning experience.

Quite difficult to determine the original winding pattern from the old motor, as not quite what I expected. Eventually worked out it was : 2 No. phase groups, each with 3No. concentrically arranged pairs of coils (1 pair coils per phase). So need to wind a nested coil pair x 6, arranged and connected appropriately to generate the 4 alternating poles.

This is where the 3d printer comes in - to produce a demountable double former to generate the concentric coil pair. Haven't got as far thinking about the winder yet - probably on the lathe faceplate with some Heath Robinson arrangement using the small cheap mechanical counters commonly available .

Thread: vfd question
26/03/2020 11:40:06
Posted by Lynne on 26/03/2020 10:32:13:

I am now reluctant to ask a question. Regards, Lynne

Why?

I thought that is what this forum is for. There is no guarantee that your problem can be resolved but it doesn't cost to ask.

Published technical guidance can be pretty obscure when you come across it for the first time, but it is usually the case that the key functions can be explained in a more helpful way.

Thread: scam alert
25/03/2020 19:44:52

indeed.

Thread: Any ideas please
25/03/2020 19:42:23

Cats have been known to work.

I did briefly experience an invasion of voles in the garage and apple seemed to work for them. I felt a bit bad after I had trapped a couple and installed a sonic thingy that I plugged into a trailing socket near where I thought they were.

That seemed to clear them out, left the device in (about the size of a 13 A plug negligible power consumption) and nothing has come back since.

Thread: scam alert
25/03/2020 19:32:22

Here is a sneaky one - may be genuine but it was tripped by my paranoia circuits.

Came as a text...

'Hi, its Dave your local SSE meter reader, I cant come into your house to read the meter due to coronavirus regs etc.... please telephone me your readings to avoid an estimated account blah blah...'

Now it just so happens my account is with SSE at the moment but they always e-mail me to remind me to update my account with the correct readings each month, so immediately suspect.

If a scam, I have no doubt that anyone responding this call would be contacted in a couple of days time along the lines of......

'Oh sir, the meter reading is fine, but there appears to be a problem with your direct debit... can you confirm your bank details etc etc...and so on.'

Thread: vfd question
24/03/2020 22:54:34

The problem with the XSY manual is its extreme brevity! In truth there is not a lot of adjustable features anyway, just the basics that are fairly straightforward as below.

Users must have regard to the VF slope - default is OK for most AC workshop motors

Ramp rate settings are self evident defaults are ok to start

Torque control is a percent setting

slowdown/braking setup straightforward

Overcurrent setting simple

The issues with VI keypad display I now believe to be due to issue of VFD pulsed output. I put my new clamp-on meter on a phase to the motor and it was in pretty good agreement with the VFD keypad.

Unfortunately the clamp-on meter has no low pass filtering so gives erroneous VI on non sine wave form, which suggest the keypad monitor also struggles to provide a RMS output of VI. Would need to find someone with a scope or a fluke analyser to do more investigation.

Thread: Fixing motor for Myford Ml7
24/03/2020 22:24:03

James,

you will find the cost of refurbishing a fractional motor will be about 3-5 times the cost of a new motor. You might get them to check over for coil condition, leaky insulation etc for only the cost of a new motor.

Unless your motor is actually malfunctioning - is slow, lacks torque, has a lot of vibration, is over heating exudes burning smells or is noisy etc there would be no reason to replace. when you get it running, allow it to run for half an hour or so and check that it doesn't get too hot

A new 3/4 Hp 1P motor will set you back £70 -80 if you shop around.

24/03/2020 10:40:48

Hmm, your plate says 3.7 A

so assuming start up current can be up to 3 times that....

Dangerous not to use a fuse, but 13A will be fine, but if that blows regularly too, then you may have a problem.

If it runs smoothly and nothing appears to get too hot then you are good to go. 

 

Edited By Martin of Wick on 24/03/2020 10:45:19

Thread: DIY induction motor rewind
24/03/2020 09:41:23

Thanks mike, hadn't thought about how the suppliers specify their wire - I guess you are saying that it is on conductor size nett.

The wire measures at 0.5mm D gross. so will re-measure with the insulation removed as it could be 0.45mm.

If I procede, I will use one of those expandable staged former thingies available from Ali. They permit winding of all four stator coils in the phase at once, each staged in length so they all come out with about the same projection from the stator when installed (about a fiver delivered).

Looking as if the materials will cost about £40 so very much a learning exercise than a money saving scheme.

24/03/2020 08:55:44

DC3, Thanks

excellent - hadn't managed to get that far in the thought process - approx. 20 ohms per phase comes out at approx. 240m x 3 worked out at about 1.3 to 1.4 Kg Cu.

Back checked to turns per stator slot coil is about 150 t, which looks about the right order (24 slots so 3x4 coils).

Will count the true turns from the original when I figure out a way to cut out the old coils (whatever it takes I suppose).

The tip about Elastoplast looks to be pretty helpful too!

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