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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 question
21/03/2020 11:27:02

It is a matter of choice, but I would be inclined to set P12 stopping mode as 0 or inertial stop but if using deceleration stop, test with regard to parameter P42 to ensure the ramp down meets your expectation.

The drawn current display on the keypad is not necessarily 100% accurate - more a guide. What is the plate rating for delta - what is the power of the motor? if you are seeing what you expect for full speed operation then all is probably OK as long as wattage is within the VFD rating. If you are getting unexpected Error 6 trips under load (ie not caused by a lock up or by using a 3in drill or other operational abuse), you may need to increase P78 or the overload protection buffer, but have regard to how tolerant your motor is.

If you want to run at higher frequency say 60Hz check the current draw at that level is not causing a trip. Also ramp the speed up and down with the pot a few times to check there are no sudden peaks in current draw as you reduce speed (yes I know there shouldn't be, but am just passing on my experience).

Even though your motor is dual voltage, run it for an extended period at 50 Hz off the controller and check you are happy with temperature- if previously running on 400v, it may be getting hotter than you are used to with the higher current draw at 220v

Edited By Martin of Wick on 21/03/2020 11:30:04

Edited By Martin of Wick on 21/03/2020 11:31:10

21/03/2020 10:43:06
Posted by john barnes 4 on 21/03/2020 10:36:59:

joseph noci 1, my instructions do not have a setting for P25 which according to the set up you posted is for number of poles. The VFD does have P25 so I will try that. I have P21 set to 1420 which I thought was for the rated speed of the motor. The VFD trips out at 1420 so I will increase that and see what happens. Thanks for your help.

P21 correct - enter plate speed which if you motor is 4 pole will 1400 or so There isn't usually a P25, as setting the motor speed performs same function (more or less). If you set a higher plate speed, only the display RPM will be affected.

21/03/2020 10:37:58
Posted by Peter Spink on 21/03/2020 10:17:51:

Is this: LINK the one?

Testing the earth continuity at 04.17 it appears that the earth is also switched via the locking pushbutton disgust
Not a good idea!

Well that is just user plain old error, not a fault of the inverter.

An earthing point is provided on the device into which themotor earth and incoming 220v mains earth should connect unswitched.

21/03/2020 10:32:29

Herein is the problem.... The unwary user will assume these are 'consumer' units because they are cheap and readily available, like some sort of pistol drill speed controller in the olden days! That they are not, they are based on industrial devices and provided with no concessions to the unwary or inexperienced. So yes beware and make your own risk assessment.

I would hope that most sensible people would check / set up their device using the panel and then construct a remote pendant to suit their requirements and secure the nasty dangerous bit in its own box.

If access to the keypad is required, it can be mounted in an enclosure so only the front upper portion is exposed.

21/03/2020 09:54:23

sit down, RTM and think logically....It is pretty simple, If you cant understand it seek help here. See one of my previous posts on a search for AT1 thread.

you should have a parameter P78 main current overload

set that at the calculated normal load current for your motor + 20% or what you feel comfortable with (it is expressed in mA so 6A would be entered as 6000)  (the default by the way is 3000 which is why you may be experiencing trouble)

set parameter P24 to 2 seconds

make sure you have set P0 through 10 correctly (not what is the table above which is for high speed spindles)

Have regard to P12 for you application

Review the ramp times P26 P34 P42 (and others if you are using them) I have come across some units Hz/s has been a multiple of 10.

Avoid using the factory reset unless you have been through all of the parameters and written them down - sometimes the defaults are not as stated on the printed sheet and I also suspect there may be some hidden non accessible ones.

Contrary to the received blather on the net, these are excellent high quality units, let down by poor end user manuals, the connections are no more exposed than in the majority of older industrial inverters. The boxes are intended for industrial panel mounted use, but sold onto the hobby market hence the howls of outrage. The Chinese assume that the people purchasing this class of device will be smart enough to enclose the devices or carry out some other form of risk mitigation.

 

 

Edited By Martin of Wick on 21/03/2020 09:55:27

Edited By Martin of Wick on 21/03/2020 09:56:58

Edited By Martin of Wick on 21/03/2020 09:58:28

Edited By Martin of Wick on 21/03/2020 10:00:11

Edited By Martin of Wick on 21/03/2020 10:03:46

Thread: Coronavirus
21/03/2020 09:24:20
Posted by Ady1 on 21/03/2020 08:23:55:

And as usual most of the sacrificing in this war is being done by the youngsters in the form of financial armageddon

While the main net beneficiaries in this war are the oldies who live in relative financial luxury

Well it is a point of view, and I would be enlightened to learn exactly how the over 65s are supposed to be benefiting from these depressing circumstances?

As has been pointed out by others, pension savings were made by forgoing other forms of instant gratification to prepare for a future that may not be benign.

You may rest assured that this crisis will be paid for, and primarily paid for by those that have scrimped and saved rather than those that lived in a dream world of no tomorrow and where debt was considered a form of free money.

Life is about to change and the era of low taxation and low inflation is about to abruptly end.

Thread: Finally got the milling machine home.
17/03/2020 07:59:52

Just do it... you will soon find out the optimum feed and speed for your face cutter and application. You don't need to have the best of the best, or the biggest of the biggest for hobby work. If in the end it doesn't remove sufficient cubic inches of metal per minute to meet your expectation, then you will need a bigger mill.

If it is of any help I use 43 and 50mm multi tooth face cutters with no problem on a WM16 with MT2 - not a rigid or powerful machine by any standards. Try 0 .5mm on ferrous and 1.0mm DOC on non ferrous say 0.,05 mm chip load at maximum RPM as a start (only 2500 rpm on the W16). I generally prefer these multi tooth jobs to single point fly cutters.

I would have thought that the TS could probably do better than a WM16, being a more substantial machine.

Thread: Coronavirus
14/03/2020 20:43:26
Posted by Plasma on 14/03/2020 19:09:45:

Am I missing something?

If normal seasonal flu kills 8000 people in the uk and this covid is not much worse why are we taking such huge measures to control it?

because it is 10 times more potent than the average flu and very serious for 15% of cases

because it is 3 to 5 times more infectious than ordinary flu

because it has a long incubation period during which the host organism is infectious while active in the population

because there is no effective treatment, cure or vaccine to slow transmission

because it now epidemic the general population and without mitigation cases are doubling every 4 days.

without some attempt at mitigation from a current case count of 1000 within two months the numbers infected could be of the order of 16 Million, if 15% needed enhanced or advanced medical care that is 2.4 million hospital beds over the period. Say each stay was approx. two weeks, that would still be in excess of 500,000 beds minimum to cover admissions for Covid-19 alone.

There are about 175000 UK hospital beds and maybe 5000 ICU beds (running at about 90% occupancy pre epidemic) so it is more than likely that an uncontrolled outbreak would completely overwhelm the medical facilities, that is why the Govt is concerned and will probably try any effective measure possible to slow the rate of infection.

 

 

 

Edited By Martin of Wick on 14/03/2020 20:44:04

Edited By Martin of Wick on 14/03/2020 20:44:35

12/03/2020 21:09:29
Posted by Kiwi Bloke on 12/03/2020 20:22:11:

Sadly, more evidence that bureaucracy exists for its own sake, in spite of demonstrably poor performance: the World Health Organization must have a huge budget, but hasn't been able to roll out a co-ordinated international response, even though one might have thought that pandemic planning would have been an important part of its work, for decades.

Not entirely fair as WHO is not an enforcement agency, they cant make other countries carry out mitigating actions, and differing countries will have differing resources and political tools. China has done well, they have the tools and the social culture that can deliver an effective response.

If you want a real example of demonstrably poor performance look to the wealthiest and most powerful nation on earth - sad, so sad.

As a species overall we seem to suffer what one could euphemistically refer to as 'learning difficulties'. Pandemics and plagues are not new and the methods of control are as old as time, and yet the same mistakes invariably made - response is always too slow, the infective agent becomes established in the population and events must take their course.

We got the UK plan B briefing this afternoon, pretty logical and in line with what has worked for every outbreak from the Black Death onwards. Essentially if you feel ill, stay in your house till you get better, don't tell the grown ups because we need to conserve resources for the really ill.

He didn't actually say nail up the front door and paint a red cross on it but I guess that is because we have other means of communication these days.....

11/03/2020 19:40:47
Posted by Pete. on 11/03/2020 18:38:33:

 

The WHO is paid off by CCP, I wouldn't believe anything coming out of China, the Italian figures are far more realistic, if the CCP spokesman, sorry, the WHO spokesman was to be believed, China wouldn't be erecting hospitals in 10 days to isolate the infected.

 

Why would the higher observed Case Fatality Rate in Italy (near 7%) be more representative than CFR for S Korea ( at 0.7%)? The wide variation across countries just illustrates how difficult it is to get to a reliable CFR. I desperately hope that the true CFR is not 7% and there is some other factor at work in Italy.

There are two issues, the number of cases/population and the case fatality rate. The overall CFR world wide is 3.6% which is well up into 1918 Spanish Flu territory, and the rate of transmission is as high or higher.

We don't know how many in the UK population will be infected eventually, but say it was 30% as an upper bound figure for Spanish flu pandemic, the projected mortality for UK would be in round terms :

CFR 3.6% = 750,000 excess deaths over 6-9 months

CFR 7% = 1,500,000 excess deaths over 6 to 9 months - basically in plague pit territory.

Before even considering the social and economic effect of numbers of the population incapacitated, these are not trivial numbers or anything to be complacent about. If you are in any doubt, go and view a few U tube vids on the Spanish flu. You would hope we would do better being a fitter and better informed population, but.....

Because the true CRF is not known, you can see why government is concerned and desperate to flatten the peak as much as possible. We are all hoping and praying CFR is as low or lower than current observed UK average of 1.3%, and that will bad enough.

 

 

Edited By Martin of Wick on 11/03/2020 19:55:42

Thread: ML7 Main Shaft Slipping?
11/03/2020 18:58:38

|…...so not sure what can be done with them in terms of parameter alteration.

Not much apart from the basic operating ones setting ramp time, under/over voltage and current, carrier . That is why the supplied manual is only 2 sheets of A4! You could play with the Hz/V relationship as min mid and max Hz/v is user selectable, but I would be a bit wary.

There are 'factors' to modify torque at low speed, but no explanation. suspect they may only increase pulse width. If you ramp it too high it will cause the motor to 'cog' (feel like it is running over a washboard) at low speeds.

 

 

Edited By Martin of Wick on 11/03/2020 18:59:09

11/03/2020 11:14:25

Theoretically, RA is quite correct, but has not taken into account the man machine interface. Some VFD users may not be aware that the reduction in speed afforded by a VFD (or other speed controller) leads to a reduction in power available at the cutting edge. Under conditions of low speed (and low power) it is quite easy to overload the motor with the resulting increase in current drawn and consequent temperature rise.

I was hoping to point out to the OP (in my simplistic way) that a VFD is not a miracle device that means an end to any requirement for managing belt or back-gear settings.

Well, it pays to read the VFD manual to check for any software controls, likewise some new motors have an embedded thermistor that the VFD can monitor to prevent overheat as another safeguard.

However, the fundamental principle remains, in the first instance use the mechanical means of spindle speed control and use the VFD to fine tune or for other adjustments. The aim being to keep the motor at or close to the design frequency where possible.

11/03/2020 09:14:49

CB

I always think VFDs should come with a Govt health warning along the lines of:

'This apparatus is no substitute for applications where mechanical reduction of shaft speed is available'

NDIY points out that it would not be wise to use the VFD at 5 Hz to run the spindle at say 50 RPM to carry out some high torque operation - most of the power will be absorbed in heating up the motor windings and very little delivered to the tool/workpiece interface.

So I am afraid you will need to get used to mechanically setting the spindle speed to the desired rate for the job and then, if required, fine tune with VFD adjustment. That way your motor and VFD will have a long and healthy life.

 

Edited By Martin of Wick on 11/03/2020 09:24:27

Thread: S7 Tail stock
10/03/2020 12:01:13

Is it causing a problem ie. when drilling for instance?

By how much is it offset?

Did you determine this error by using two newly cut centres (made on the lathe in question)?

If not, how confident in your centres are you? if you rotate the centres does the error vary?

Did you lock up the tailstock and barrel when measuring?

Did you check if the error varied at differing tailstock extensions?

Did you take the unit of and check for bits of swarf, burr etc on the sole of the tailstock?

answers to these points may help identify the cause of the error.

 

Edited By Martin of Wick on 10/03/2020 12:02:37

Edited By Martin of Wick on 10/03/2020 12:03:58

Edited By Martin of Wick on 10/03/2020 12:07:22

Thread: Boiler bush material
10/03/2020 10:33:47

|This document would be of great interest to the model engineer.....

At £250 ex BSI,  my interest seemed to rapidly diminish for some reason

 

Edited By Martin of Wick on 10/03/2020 10:58:18

Thread: Super 7 lubrication
05/03/2020 12:10:38

You could try Pressparts, their pressure oiler is considerably less leaky than the official version and the price retains contact with reality.

link **LINK**

Thread: Mini Lathe
04/03/2020 15:10:36

I wouldn't fret about it, you have done pretty well.

From new, my mini lathe tailstock came offset in the Y axis and not parallel to the bed with respect to Z AND with a bloody great burr in the MT2 taper AND with the barrel clamping bolt stripped.

So you can see why they have the reputation they have, but once you have taken a bit of time to sort the minor niggles out they are perfectly satisfactory machines for most small jobs.

Edited By Martin of Wick on 04/03/2020 15:12:12

Thread: VFD remote (pendant) design
03/03/2020 09:44:55

|…...I didn't give it much thought - and I'm not an electrical guru).....

Hmm... looks more like a bit of overthinking going on!

Through the advent of VFD control electronics, you have all the benefits of digital power switching, so use that to control the power side and use the wall switch to turn the VFD on and off. You don't need contactors, isolators, NVRs etc. and all of the old electromechanical crap from the past - the VFD takes care of all that.

The LV control side is about as complicated as wiring a 13A mains plug but less dangerous as it is LV!

 

 

Edited By Martin of Wick on 03/03/2020 09:47:58

Edited By Martin of Wick on 03/03/2020 09:54:18

02/03/2020 19:38:00

You don't need industrial grade switch-ware for hobby use especially as it is only low VI stuff.

I get the cheapest and nastiest I can find by way of 22mm push button stuff or 35mm rocker/toggle switches from the usual fare eastern marketplaces. Ditto large rotary switches if you prefer these. I tend to go reasonably large as don't want to faffing about with 10mm stuff and micro switches. A big red button is always a comforting sight.

Search on 22mm push button etc...

A lot will depend on how you want to configure your controls ie press and release or switch etc. Also recommend getting push switches configurable as both NO or NC on the same block, gives you more options in case your VFD turns out picky.

For pots go for a sensibly large 1 turn wirewound 2-5 watt unit for mechanical robustness £2 to3 each or less in bulk via aliexcess. Avoid multiturn pots unless you enjoy a lot of twirling of controls - just my view.

I don't bother with decent looking - some sort of plastic box and label with my lidl Brother style tape labeller - sorry to be so unprofessional.

Thread: AT1 inverter 3 wire control
01/03/2020 11:29:59

For anybody struggling with the XSY AT series VFD manual cryptic control parameter descriptions, based on my limited testing. I hope this will be useful to someone. Further details set out below:

As suspected, all 6 of the analogue inputs are configure as active high, meaning the control logic is activated by an input signal and not an interruption of signal. There appears to be no way of changing this.

The VFD in its default state set no signal input to the non running condition.

The permissible control inputs are restricted, but do allow for continuous contacts via a latching switch (described as 'wire' switching, or momentary contact via a non latching push button arrangement described as 'key or keying'. The more useful input parameters for the 6 analogue input block locations 50 to 55 are as follow:

PARAM 1 wire control stop  This changes the VFD default condition to run on power. With contact between com and terminal, the attached motor will not run. with no contact, the device will revert to the previous control state. It is unlikely that many workshop users will need to use this parameter.

PARAM 2 keying stop   should really say key start/stop This uses a single non latching push button control to activate the motor. Push the button once for on, push same button again to turn off. It requires a contact set that is NO, or 'push to make' linking com and the terminal set as P2. useful if you only have one button!

PARAM 3 keying operation This changes state from deafault non run condition to the motor run condition and uses a single non latching push button control with a contact set that is NO. Pushing the button starts the motor, further button pushes have no effect unless the status has been changed by the input to another terminal.

PARAM 4 stop keying This changes control state from the run condition to a stop condition and uses a single non latching push button control with a contact set that is NO. Pushing the button changes motor run state to motor off but will have no effect ( it may however interrupt jog mode if pressed during jogging ops). P3 and 4 are used normally used together to effect two button RUN and STOP controls (if that is what you want).

PARAM 5 and 6 wire forward operation wire reverse operation These require a latched contact between com and terminal. Forward and reverse are relative conditions, so need to be set in the context of your particular application. used if a toggle switch or rotary switch operation is required. For example, you might set com on the centre of a 3 way switch wit rev one way and forward as the other. HAVE A CARE as leaving the machine switched to run and starting the VFD a couple of days later without remembering will result in a start up on powering the VFD. you may want to set parameter 1 in location 65 to avoid this.

PARAM 9 wire reversing switch This changes the run state from forward to reverse. When latched, setting the motor to run by another terminal, will cause the motor to run in the reverse direction. Unlatching will restore the original direction of rotation. Normally used with a simple toggle/rocker switch in conjunction with a wire run or key run input.

PARAM 10, 11,12 keying commands These are not well described in the manual. P10 should really say Key forward/reverse switching). They are all momentary inputs requiring non latching NO push button control. P10 allows a single push button to change motor direction, pressing the will reverse the current run direction and so on backwards and forwards. This function will only operate in conjunction with other keying commands (ie P3 or 11 or 12 in the active condition). P11 will start the motor only in the forward direction, P 12 will start the motor only in the reverse direction.

PARAM 17,18 jog forward / reverse Self evident, use if you want a jog function. Can be used with a latching switch to connect com to terminal to hold in jog or NO non latching if you just want to 'blip' the rotation for a part rotation. See params 86 onward for controlling the jog frequency braking etc.

PARAM 19 E stop FWIW, a stop switch and all round missed opportunity. Requires a NO contact mode for your e-stop input. Can be implemented as latching or instant. Latching is preferable as it sets an interlock and prevents normal or jog start until unlatched. If you don't have a latching e-stop, I suggest you also wire into another terminal set with P16 so it sets a fault condition at the drive as ERR 9 preventing further unwanted starts until the cause of the panic has been sorted and the VFD re-set.

Unfortunately, there appears to be no way of setting a braking function on the E-stop, the condition when you most want to stop the rotation instantly. You can set the brake to operate on the normal stop where you don't really need it, but it doesn't implement in the E-stop. Grind your teeth in rage if you will, but remember how little you paid for the device.

 

 

 

 

Edited By Martin of Wick on 01/03/2020 11:32:05

Edited By Martin of Wick on 01/03/2020 11:34:02

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