Installation of a Hitachi WJ200 VFD and changes to the control switches on a PM1340GT lathe

[Falcon67]

FWIW - Here's how I separated my motor and control wiring on my mill. Each travels to the mill in separate shields. Not exactly applicable to the above install since the VFD is mounting on the lathe, but might be if the VFD was mounted remote. The 240V power switch is a Grizzly part that is good for 2HP and has a manual lock out feature.

I have a 4 year old grandson that likes to go in the shop a lot. He figures out what levers and switches can do what pretty quick so everything in the shop is off and/or locked out.

 

[mksj]

I have not seen this as an issue nor mentioned as a requirement with this size of single phase input VFD converters and service ratings that a hobby machinist would encounter. The warnings mentioned deal with a power supply 10X the inverter rating or >500KVa (and sometimes very long supply runs). An input reactor on larger VFDs will attenuated the inrush current, but I have not heard of this being used outside of an industrial setting. They present their own set of issues and are very costly.

As Jim mentioned, the input house wiring between your service entrance and the VFD provides some inrush protection, and the circuit breaker would trip if it the inrush current was too high. The size of the capacitors in these single phase input VFDs is quite small, my stereo amplifiers have about 20X the capacitance, and the lights dim for a few seconds when they turn on. I do not leave them on all the time, so the capacitors get charged/discharged usually daily for years. Large power amplifiers sometimes do use a thermistor or switched line resistor for a soft start. VFDs that have been sitting for a long time unused, it is recommended to turn them on, but not run the motor for a period of time. Older electrolytic capacitors sometimes needed reforming by slowly bringing up the applied voltage, modern electrolytic capacitors this is not an issue. If this was a significant issues, there would be a much higher VFD failure rate, and companies would be quick to incorporate it into their VFDs.

I have multiple VFDs on different equipment, each is wired to a machine's mains switch. I do not leave them on, they are shut off when I am finished with my work on that machine/done for the day. Reminds a bit of the discussion years ago about leaving computers on all the time or shutting them off. These days, we turn them off/hibernate mode.

I am not familiar with the VFD requirements in the industrial setting, but this would be a different animal. Nice review of some of the issues discussed. http://www.danfoss.com/nr/rdonlyres/b3175b64-f8f4-46d4-95d4-2491f3cca03c/0/vfdlesson5.pdf

 

[tnbubba]

firths thansk a tonn save me hours of work!
brain burp but I am puttting the WJ 200 in a sererate box on top of the G0709 control box.. pop a few holes and then can tap into all the stock switch switch wiring and have the VFD and power wiring in the top box I will use the touch pad to control the freq up and down my questiosn is how does the VFD handle the inevitable "oh crap" when you throw the spindle lever from forward to reverse?

 

[mksj]

how does the VFD handle the inevitable "oh crap" when you throw the spindle lever from forward to reverse

The VFD doesn't care, it will ramp down to a stop and then reverse per the deceleration/acceleration VFD parameters. It is not like reversing a standard motor which puts a lot more stress on the gear train. On normal use I set my VFD braking to 2.0-2.5 seconds, but the E-Stop, proximity sensor or any interlock switch reverts the VFD to 1 second braking. This puts more stress on the gear train so it is only used for low speed threading/turning to a stop/shoulder. It requires a braking resistor, which is pretty much mandatory for shorter deceleration times and machines with momentum in the drive system. On threading, there is less momentum if you use a high speed gear selection and turn down the VFD speed.
Mark

 

[tnbubba]

THANKS.. I assumed such, but been thru that hitachi manual several times and never found a definitive answer.. my biggest PITA is getting the G0709 wiring sorted out to find which lead is which since Grizzly manuals don't show the wire numbers and some of the controls and switch logic is screwy.
got to find me a cheap braking resistor. For now it will operate without one and use my foot brake for speedy whoa's . Have you found any benefit with the autotune and SV control? and yes for you other guys I have a 30A rotary switch to turn off the VFD when the lathe is not in use. No need to worry about inruch currents..LMAO I have a 1400W / channel amp in my home system with abotut 150K Uf of capacitor banks.. now that sucker will dim the lights when you switch it on!