Hitachi Wj200 issues

Search my name and Hitachi on Practical Machinist. I had a similar problem and a Hitachi tech jumped right on and helped me out. Maybe you could message him or just call their support line. They are pretty good.

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Jonesturf said:
Search my name and Hitachi on Practical Machinist. I had a similar problem and a Hitachi tech jumped right on and helped me out. Maybe you could message him or just call their support line. They are pretty good.

I called Hitachi yesterday and talked to Sam. We ran all the appropriate test and even though the results show that it is operating normally it has no output to the motor. He thinks something is fried inside. I know most electronic devices are divided into 3 groups, input, process and output. Since the unit appears to be operating normally I can assume that the problem will be in the output circuitry. In the old days I would have initially suspect a power transistor.
Other than the leads Im not even sure I can identify the output section. I don't really have anything to loose at this point so I think I will dissemble it and look for heat residue. I will post what I find if anything.
Thanks everyone for your assistance.
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by any chance is the program led flashing when you try to run? If it is then you have a programming error and need to undo the error or do a factory reset b084 followed by b031 then re-enter all your settings one at a time making sure you don't end up with a flashing program led. Bob
 
vettebob

Well you may have something there.

I removed the unit to inspect for heat damaged components and reinstalled it and it's working fine now!

I do remember the program light staying on at some point during the initial attempts to reset F004. At the time I thought I must have happened because I didn't wait for the spindle to stop. Its been too long now for me to accurately remember, but it certainly looks like operator error.

Sam's analysis of a bad unit was based on incorrect information from me. I stated that there was no measurable output to the motor when the run lights were on. That was based on using a negative ground, I didn't think of checking for a positive ground reference until I reinstalled the unit. When I did I realized that it was functioning normally. I went through the initial prog pushed on the arrow and she fired right up.

So THANKS everyone for the help, Im still not exactly sure what happened but I learned a lot in the process.
 
Even though the Lathe and Mill have the same size motor the loads are considerably different. The lathe is a high inertia load while the mill is a lower inertia load. This is due to the mass and size of the different chucks. The high inertia load of the lathe is much harder for the regulator in the drive to control and nearly impossible to control when you reverse direction as the inertia will generate voltage back into the drive which it cannot handle. This is most likely the reason for the tripping of the drive. only two ways to try to control this, one is to increase the decell and accell of the drive. the other is to add a dynamic brake resister and turn on the dynamic breaking on. You don't have to spend a lot of money on the breaking resistor. Hass uses electric stove heating elements as dynamic breaking resisters it's not pretty but works real good. Just make sure the resistance of the heating element is no lower than what is recommended by the drive manufacture and the resistance should be within 10 to 15% of what is recommended.

As far as the erratic behavior of the drives programming. The first thing to do is to reset the drive to the factory defaults and reprogram the drive. you also need to check the wiring and installation. proper grounding of the system is very important. you must run a ground wire from the motors ground point in the connection box to the ground on the drive. this allows the drive to control the common mode currents in the system. conduit pipe, and the machine frame do not count as a good ground. There must be a ground wire from the drives ground to the electrical ground in your wiring. if you do not have a grounded wiring system you will always have issues with electrical noise and the drive could give you intermittent trips and perhaps fail. lastly if you are running on 115 single phase power and the motor is relatively large and the shop wiring is relatively small (15 amp) the voltage feeding the drive may be dropping when you start the drive with a high inertia load this would also be true in a 3 phase system.

Jim Nunn
 
Thanks Jim I appreciate your input.
I think I will leave the VFD on the mill and not switch it between the two machines, that should take care of most of the issue. I hadn't planned on using the VFD on the lathe at all but haven't started on building a RPC and wanted to test run the lathe. I have several other 3ph consumers so I need to get going on that project.
The motors are not large (3hp) and the service is dedicated, 20A, 220v 10/3+G, so it should be sufficient. I will install another ground wire, as you suggested, between the VFD ground and the motor case.
 
Your WJ200 will give the fault code of why it tripped. There is 2 pages of them in your book. With that it will be easy to solve your problem. Also did you run auto tune? Did you set the number of poles on your motor? The drive should not trip when going from forward to reverse as it automatically montors rpm and does not switch until it's safe to do so. You may have braking enabled and may be tripping on an over voltage as stated by one of the other members. Bob
 
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Hummph back to the same problem.
I used the mill for one operation with multiple on and off cycles and it worked fine. I tried to use it last week and it presented the same symptoms. It was depowered for two weeks while I installed an RPC for the lathe.
I did not make any program changes during the prior use or before the first attempted start last week.
The program light is not on. run annunciator is lit and the run led illuminates when run is pressed but the motor doesn't turn or make any noise. (except as noted below)
I use the keypad for control.
I reset factory defaults, and re initialized the basic startup procedure from the manual, with no change in the results.
I don't have a laptop but printed the material referenced in Mksj's response for additional information. Referencing that information I changed the a044 setting from oo(constant torque) to 03 (sensorless vector).
Now it starts turns very slowly, maybe 10rpm but doesn't respond to the incr /decr arrows on the keypad. Obviously speed control is the constant issue here.
My preference is to have the mill run at a constant speed and mechanically change the speed.
How do I do that?
 
Just a thought, earlier in the thread you mentioned using the forward/reverse switch on the mill... Is the Hitachi rated for interruption of the motor side? Many VFD's become very unhappy when the load is disconnected while the are powered up.

paul
 
Hi Paul
Thanks for the reply.
My wording was rather ambiguous in the original post. There are no devices between the vfd and the motor.. I use the programmable input at F004 to accomplish reversing.

Howard
 
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