[cnc3678]

Hello,

I'm attempting to fire up my Chinese 2.2kW spindle for the first time using a Hitachi WJ200 inverter. I've correctly wired the three phases and connected the spindle with a shielded cable (shielding earthed at one end only). The inverter seems to be correctly configured with input voltage/freq and current limit settings.

When I hit start button, the spindle starts turning very slowly (5-10 rpm) and makes a strange buzzing sound. After about 5-20 secs, the inverter trips out with an over-current alarm.

Any ideas? Does someone have a standard config for the WJ200 that I could look at?

Regards, Richard

[bill south]

Make sure that the inverter frequency is set for the 400 hz spindle. That would be my first guess.
B

[cnc3678]

Already checked. I've set min freq to 50hz and max to 400hz. I'm getting access to a cro tonight to have a look at the wave forms.

[cnc3678]

It now appears that the VFD is OK as I managed to connect a different 3 phase motor and it worked fine at 50hz.

So it looks like I have a problem with the spindle. Any ideas as I don't think I'll get a refund (purchased it over 12 months ago). Anyone one had problems with the windings on these cheap Chinese ones?

[Dylwad]

I would take the rear cover off and check the connections. First thing I did to mine was replace the cheap Connector with something better. The rest of the spindle has been flawless for close to a year, no complaints...

From tapatalk

[cnc3678]

Good thought, but I had already changed the plug before I started using it.

[mactec54]

cnc3678

I would say you have not set the VFD correct, were you have the 50hz setting this has to be 400hz too, there are other settings as well, but do this first, another one you will have to set the ramp up time & the ramp down time as well or it will trip out in over load

[bushwakka]

A growly noise and no rotation sounds like you could be losing a phase between the inverter and the spindle. Check the plug/socket on the top of the spindle - i suggest replacing them with an amphenol plug and socket, and connecting an earth while you have it open. If you have changed it already, then check that all three phase wires are connected (can to it as below without the cable).

If you have a multimeter, disconnect the cable to the spindle motor at the inverter. On the cable (disconnected from inverter, so no power on it), measure resistance between 2 phases x3 and make sure the numbers are all consistent (they should be low numbers as it is only the resistance of the cable and the winding).

Let me know the resistance results and we can go from there.

Paul

[cnc3678]

Thanks Paul, I'm already using a new amphenol plug and socket but I will now open the spindle up again and double check everything. Good point about checking winding resistance to see if there is consistency across the three phases (I'm assuming the're wired in delta).

Mactech54 - Thanks for your suggestion as well. Originally I had the inverter configured to run at 400Hz max, but the test motor is rated at 50Hz and hence the reason why I lowered the output frequency. The ramp up and down time is set for 10 secs and this worked fine on the other motor.

Richard

[mactec54]

cnc3678

Your settings should look something like this

A001- 00
A002 – 02
A004- 400HZ
A003 – 400Hz is Spindle base frequency
A061 – 400HZ
A062 – 0
A082 – 230V/240V
A151- 0
A152 – 400HZ
A153 – 0
A154 – 100
A155 - 00
B012 – 10 Amps of your spindle
H003 – 2.2 KW this is your spindle kw rating
H004 - 2 poles most of these spindles are only 2 pole

[bushwakka]

I've never really looked at the internal connection. Delta connection would be most obvious.

I have a spindle open here and get about 1.6ohm between each pair of wires. This could vary an ohm or 2 depending on your leads lengths etc.

Paul.

[cnc3678]

Thanks Mactec54, I'll compare these settings to mine and report back.

Richard

[bushwakka]

Just thought of something else to check. Is there a parameter in the inverter that sets how quickly the inverter accelerates to the required frequency. It may be accelerating too quickly for the spindle to keep up.

Paul

[cnc3678]

Thanks to Mactec54, I've found the problem and it came down to a single setting on the inverter.

A003 – spindle base frequency was set to 50Hz and changing it to 400Hz fixed the problem. This is despite the manual suggesting that this 'base' value should be set to 50Hz or 60Hz as shown in the picture below. Hence setting the max frequency to 400 Hz (A004) wasn't enough and required the A003 base frequency to be set to this value as well.

So I'm very relieved, but a little fustrated that I wasted a number of hours of testing and pulling down the spindle.

Richard

[mactec54]

cnc3678

Your spindle base frequency is 400hz, so needed to be set to the 400hz

The 3ph motor you tested the VFD with, had a base frequency of 50hz this would be the setting for that motor

[cnc3678]

Mactec54,

thanks again for your help. From your experience, what's the lowest frequency that these spindles will operate at without losing too much torque (or getting too hot)?

Or is this a limitation of the inverter capability?

[Dylwad]

Mactec54,

thanks again for your help. From your experience, what's the lowest frequency that these spindles will operate at without losing too much torque (or getting too hot)?

Or is this a limitation of the inverter capability?

The 8000-24000 rpm rating on the motor seems about right to me.

From tapatalk

[bushwakka]

In theory the torque should remain reasonably constant, but without an encoder feedback for the inverter, the torque drops away as frequency decreases.

Power is proportional to Torque x angular velocity, so a 24000rpm rated spindle will be
2.2kW @ 24000rpm
1.1kW @ 12000rpm
about 750W @ 8000rpm
and dropping away to not much power at all below that.

Cheers
Paul

[cnc3678]

Another question.

I'm using a Gecko G540 controller and have been able to use the 0-10v analog output to control the speed successfully on the inverter. However I'm keen to also control run/stop and can't figure out how to wire one of the Gecko's output's to the WJ200's input terminals? Can someone help?

Many thanks

[cnc3678]

Worked it out. Just needed to wire one of the g540 outputs to a 48v relay. On the relay side, I ran one of the wires to the WJ-200 digital input 1 and the other to ground. Then set A002 to 1 which switched the RUN control to the digital input.

Works a treat.