Inverter

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Stub Mandrel on 16/11/2013 15:56:36:

and to calculate when the motor is at risk of overheating through slow running.

I don't understand how it can do that as motors vary in their ventilation characteristics. I am using Magnetti Marelli (sp.?) motors that are designed for inverter speed control and have a higher airflow than normal. I guess it must make some assumption about motor characteristics.

Personally, I just feel the case temperature by hand occasionally if slow running for extended periods.

Russell.

[Thor 🇳🇴Participant @thor]

Hi Paul,

I haven't tried overheating the motor to see if the inverter shuts it down. But I had a small accident that stalled the lathe, and the inverter immediately shut off the supply to the motor so no harm was done.

Russel, I do as you do, feel the case temperature by hand and if I feel the motor is getting hot, either shut it down or let it run at high speed (without load).

Thor

[Hairy PeteParticipant @hairypete39644]

I don't understand how it can do that as motors vary in their ventilation characteristics.

The VFD monitors the resistive component of the winding. The temperature coefficient of copper is 0.39% per degree, or about 20% change for 50 degree increase – easily detectable.

[Sub MandrelParticipant @submandrel]

It issues a warning (which you can set to trigger an output) and if you carry on it stops the motor and gives an error code.

It makes assumptions about the motor's 'thermal constant' which is given in seconds. Like many system variables this is set to a typical value and can be reprogrammed (presumably by those with lots of time on their hands or professionals setting up VFD/motor pairs for specific applications).

Neil

[_Paul_Participant @_paul_]

Posted by Russell Eberhardt on 16/11/2013 16:50:58:

Personally, I just feel the case temperature by hand occasionally if slow running for extended periods.

Russell.

+1

And if you can smell burning insulation resin it's also time to give it a bit of a rest

Thor,

If I occasionally "jam" the Teco driven Bridgeport it does exactly the same but then it takes a complete shutdown of the inverter for it to recover, iv'e often wondered if this shouldn't be more of an E-Stop type event?

Paul

[_Paul_Participant @_paul_]

Posted by Stub Mandrel on 16/11/2013 18:41:55:

It issues a warning (which you can set to trigger an output) and if you carry on it stops the motor and gives an error code.

It makes assumptions about the motor's 'thermal constant' which is given in seconds. Like many system variables this is set to a typical value and can be reprogrammed (presumably by those with lots of time on their hands or professionals setting up VFD/motor pairs for specific applications).

Neil

Yes know what you mean some of the manuals/menu's are like wading through treacle.

So to fix this you could:

Fit a temp sensor on the motor wired to say an Arduino to do two things:

Once it hits "X" temp switch in an external fan you have secreted on the motor

If temp still rises then trigger an E-Stop on the inverter but leaving the external fan running till the temp reaches an acceptable/normal level.

Paul

[Sub MandrelParticipant @submandrel]

My motor has a temperature sensor built in and the inverter knows how to use it (if I can give it the spec) but I don't know the spec of the sensor, beacuse I bought a vanilla motor and the sensor seesms to be an unexpected extra, not mentioned in the motor manual

Neil

[I.M. OUTAHEREParticipant @i-m-outahere]

Posted by Ian Phillips on 16/11/2013 09:32:47:

Ian (Slo…)

My first thought was that a log pot had inadvertently been used. As its not then something else is clearly amiss. Is the fact you mentioned wrongly labelled terminals a clue?

I have not heard of the manufacturer you mentioned, nor of a VFD that did not work out of the box (after making a few simple checks or changes).

What is the documentation like? does it give proper wiring diagrams and input output details of each connection? I would assume the pot is wired across a reference supply and the wiper feeds an analogue input terminal. It sounds (just possibly) that the pot is wired incorrectly.

Hi Ian P,

Yes the pot is connected between a 10v ref voltage and the analogue common with the wiper connected to analogue input as per the wiring diagram but I will check the terminal designation to ensure they are marked correctly , the on board pot is the same as the rpm increase is not linear it seems to be bunched up at one end of the pot travel

I'm also starting to think there may be something in the programming that is causing it as there is provision for changing the voltage and frequency curve but I have left this well alone for the moment as the manual is a bit sketchy about this .
I'm also starting to wonder if the frequency curve is linear between 0 and 400hz and by setting the maximum frequency to 60hz as I have means that i'm only using around 1/6 of the frequency curve in the VFD and this would be close to the amount of travel that the pot is using to give me 0 to 60hz on the VFD display ?
Something I will have to play with today I suppose.

Ian

[John RuddParticipant @johnrudd16576]

Posted by SLOTDRILLER on 16/11/2013 21:52:05:

I'm also starting to wonder if the frequency curve is linear between 0 and 400hz and by setting the maximum frequency to 60hz as I have means that i'm only using around 1/6 of the frequency curve in the VFD and this would be close to the amount of travel that the pot is using to give me 0 to 60hz on the VFD display ?
Something I will have to play with today I suppose.

Ian

Slotdriller,

Which make/model of VFD are you using?

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Hairy Pete on 16/11/2013 18:17:54:

I don't understand how it can do that as motors vary in their ventilation characteristics.

The VFD monitors the resistive component of the winding. The temperature coefficient of copper is 0.39% per degree, or about 20% change for 50 degree increase – easily detectable.

That sounds reasonable, however it means that it is measuring the actual temperature not "calculating when the motor is at risk of overheating through slow running"

Russell.

[I.M. OUTAHEREParticipant @i-m-outahere]

Hi John,

The VFD is a HUANYANG HY03D023B 3KW 220V.

From the manual the model number equates to : HY = TRADE MARK

03D0= 3KW

B = SOFTWARE VERSION.

I have had a scout around on a few different forums and there seems to be a few inverter units not working straight out of the box and I had to go through the entire list of parameters to ensure the factory settings were set correctly , the main settings that were wrong were frequency settings and I would think they were set for the small 3ph spindle motors that they sell.

I suppose that for the money one can't complain.

Ian

[Sub MandrelParticipant @submandrel]

You may find there is a mode where you can step through settings (but not edit them) that only displays those that have been changed from the default in the manual. I solved an issue (caused by me) with mine this way.

Neil

[John RuddParticipant @johnrudd16576]

Sslotdrill/Ian,

I have the same units, I'll check what the programmed parameters are and get back to you….

I struggled at first when I tried programming mine but have a good idea on these units now…

[John RuddParticipant @johnrudd16576]

Ok here's what parameters are programmed in mine to make it run at 75 hz…..( I have a 1.1kw motor running at 1400-ish rpm its a standard 4 pole motor and I run it at 1.5 times speed)

Parameter

Pd000=0, parameter lock

Pd001=1, Source of run cmd

Pd002=2, source of frequency

Pd003= 75.0, main frequency

Pd004= 50, base freq.

Pd005= 75, Max op freq

Pd006= 2.5, intermed freq

Pd007= 0.5, min freq

Pd008= 220, motor volts

Pd023= 1, Rev. rotation enable

Pd024=1, STOP ….dont matter…

Pd025= 0, start mode

The setttings below are for running from the i/o terminals.

Pd044=2,

Pd045=03

Everything else is set as factory default, so should be ok….

Any probs give me a shout..

[I.M. OUTAHEREParticipant @i-m-outahere]

Thanks John I will have a look through my settings and see if there is anything amiss .

I know that PD004,006,007&008 are the same as yours .

Ian

[I.M. OUTAHEREParticipant @i-m-outahere]

Ok I have gone through the entire list of program settings again , had a play with the wiring of the pot , tried a logarithmic and linear pot and tried the 5v ref voltage instead of the 10v but nothing has changed .

So it was back to the internet for a good search and on one forum there was a suggestion of using 2 pots in series so I gave that a go and it worked .
So the 10v ref now connects to the wiper of a 1mohm pot (pot1) and one of the outer pins of pot 1 connects to one of the outer pins of the second pot a 10komh unit (pot 2 )- the other outer pin of pot 1 is not connected . the other outer pin of pot2 is connected to the ground terminal and the wiper of pot (2) goes to v1.

So how do you set it ?
Easy , turn on the vfd , press start with both pots wound fully clockwise and if all is well you should only get the lowest speed or some humming from the motor .
If the machine spins up to speed try winding the 1mohm pot the other way and the speed should slow to a stop or your lowest speed setting as per the internal programming .
Now you want to check if the other pot is wired to give a speed increase as you turn it clockwise so wind the 1mohm pot back a little to get say half speed and see which way the 10kohm pot has to turn to get a speed change , if it slows down when turned clockwise you need to switch the connections on the two outer terminals of this 10kohm pot (leave the wiper or middle connection alone )

If if the 1mohm pot is backwards switch the outer terminal only as the 10v ref stays on the middle connector .
So now we have sorted that out wind everything clockwise and start up the vfd again then simply wind the 1mohm pot anti clockwise until you just get the maximum frequency as set in the programming and you should find that by turning the 10kohm pot anti clockwise the speed slows over the entire travel of the pot

Sounds complicated but once I tried it I found it simple and the 1mohm pot is now mounted in the bottom of the vfd unit with a dial type knob and a reference mark to re set it if needed .

But wait there's more !
Now say you have your max frequency set at 75hz for example but most of the time 50hz is all you would use you simply turn the 1mohm pot to this setting and you have a maximum frequency of 50hz without changing any programmes ! If you want to go back to 75 hz simply wind it back to get what you want on the vfd display .

So the 10kohm pot is your fine speed control and the 1mohm pot is your course speed control .

Apologies for the long winded-probably confusing post and for hi jacking the OP somewhat .

Ian

[frank brownParticipant @frankbrown22225]

At work I came across thermistor protected motors. The thermistors were 600 Ohms and went high when over temperature. They were extremely unreliable and would go open circuit and hence the control gear would switch off the motor and the TV transmitter would fall to reduced power!!

Frank

[Russell EberhardtParticipant @russelleberhardt48058]

Motor driven TV transmitter? Was the motor used to drive the Nipkow disk?

Russell;

[I.M. OUTAHEREParticipant @i-m-outahere]

Hi all,

Well it looks as Ian Phillips is correct about the wiring of the pot .
And there is a program to cater for this .
In the picture below you will see the wiring diagram for the 10k pot (mid picture L/H side )
As drawn the pot is connected across the VR (10v) and the ACM terminal and the wiper connected to the V1 terminal .
If I go into program 70 I can change from voltage sensing to current sensing and the unit will work only when voltage sensing is set when configured like this but 0- full speed achieved in the first 1/3-1/2 of the pot travel as described in my previous post .
So I decided to try disconnecting the ACM terminal and connecting the AI terminal instead and changed the setting in program 70 to current sensing (0-20ma) and away it went ! I now get a speed change over about 75% of the pot travel .
I'm not sure what the little circle is that is connected between the ACM and AI terminal and the mostly useless manual does not elaborate on this either , maybe it is Chinese for optional !

The terminals that were marked incorrectly are the ones at bottom left SPH was ok but SPM &SPI were reversed or the printing in the manual is wrong , I have set these up for emergency stop and fwd /rev jog .

Ian

[Russell EberhardtParticipant @russelleberhardt48058]

If there isn't a setting to change the voltage sensing input voltage range you can just insert a 10 k fixed resistor between the pot and VR(+10V).

Russell.

[Ian PParticipant @ianp]

Ian

The main thing is that you have got it working but I still feel its not quite right. I would have expected that all of the pot travel would be used rather than the 75% or so you mention.

My interpretation of the terminal markings in your diagram would be:

VR = Reference Voltage
VI = Voltage In
ACM = Analogue Common
AI = Analogue In?

The first three, I would be 100% confident about but only 95% for the AI.

The unmarked circle represents whatever the Chinese says! Its most likely an alternative input for current control. Since the circle is only 'two terminal' it will need to be driven by a floating current device but some tests with a meter should be a able to diagnose what it happening there. Ironically they do show the VFD internal wiring for the digital outputs but not the inputs.

Another thought, In this wonderful web world, I wonder if there an method of inputting an image of the Chinese characters and getting it translated online?

What is the brand name of these inverters, I think I will ovoid them! (Unless they are a bargain!)

Ian P

[John RuddParticipant @johnrudd16576]

Item number 260937540695 on eBay …..

[Jeff DaymanParticipant @jeffdayman43397]

The symbols directly under the motor symbol, next to the switch, read "electrocute caucasians now, with this button"

(I think)

Sorry I don't know more.

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Ian Phillips on 19/11/2013 07:49:22:

AI = Analogue In?

The first three, I would be 100% confident about but only 95% for the AI.

AI = Amps (current) In ???

Russell.

[Ian PParticipant @ianp]

Posted by Russell Eberhardt on 19/11/2013 16:31:53:

Posted by Ian Phillips on 19/11/2013 07:49:22:

AI = Analogue In?

The first three, I would be 100% confident about but only 95% for the AI.

AI = Amps (current) In ???

Russell.

Doubtful really, its unlikely that would use the same letter as they correctly use for analogue.

'I' is the symbol for current really, but that would add even more confusion here. The eBay listing does not actually clarify anything either but Ian S has got it working so its not important now.

Ian P

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