Opinions needed! VFD, what brand and where to buy?

[toofazt]

Patio, that was a very helpful post. I also have a WJ200 and that would of helped a lot if I found it before deciphering the manual. So far I have everything hooked up (potentiometer, fwd,stop,rev) but I can't figure out how to hook up the emergency button. From your wiring diagram it looks like you changed the jumper from the stock sink logic (PLC-P24) to source logic (L-PLC). What was the reasoning behind this? I can't understand the differences in the manual. Right now I have everything wired with sink logic and it looks like our wiring is the same except you use P24 (which is 24volts) and I use L (which is ground)...

Do you know how to wire in a braking resistor?

Now that you've had your setup for close to a year, how is it working for you? Do you find you use the jog button much or is it easier to rotate the spindle by hand?

Thanks for any help!

[Patio]

I posted this answer to toofazt in a pm, but thought it would be helpful for other if it was posted here too.

"I do not know how set up a breaking resistor yet. Lakeside is very knowledgeable about VFDs. He is the one that helped me set mine up. Lakeside did recommend using a car block heater for the breaking resistor. Just make sure the resistance value matches what the VFD requires.

It has been awhile since I set this up, so I am not exactly sure why I used source logic. It may be required to be able to use the free running stop mode with the e-stop button. This is setup with switch 2 on the VFD for terminal inputs 4 and 3. Set to GS1 and GS2."

[Long Tom]

Hey folks! Great thread.

I have a 10 HP Hitachi VFD derated to give 5 HP with single-phase input. It is powering a Webb lathe with a 5 HP motor. Anyone know if the $25 engine block heater would work as a braking resistor for a 5 HP unit? Maybe a couple of them? I priced the resistor from DW and MAN they are proud of those things! It would be nice to have more braking than the VFD can currently (haha) handle. It's a fairly heavy lathe, and my chucks are 10" and 12", so there's a lot of rotating mass.

The Hitachi appears to be BUILT, but boy is that manual a PITA to decipher. It somehow manages to present the info in an almost unintelligible way. The Quick Start guide is particularly bad. Once I got the machine up and running I ceased trying to dig into that dastardly manual.

One comment is that I have the little remote panel mounted up where it's easy to get to, and I would contest that it's fragile (knock on wood). I use it every day and it's held up fine. The blisters over the buttons are tough. Tougher than the ones on my Automation Direct remote panels on my other VFD's. However, the Hitachi remote panel lacks a reverse button which boggles my mind. I was power-tapping a bunch of 5/8-11 in T304 last week and reversing the spindle via keystrokes was annoying.

[lakeside53]

Post the exact model number of the Hitachi VFD and I'll match a braking resistor(s) of some inexpensive type for you. You can't just "add two" in parallel with some computation wrt the min resistance.

It's dead easy to add the external pot and switches for your Hitachi. The vfd keypad or remote keypad is really only for data entry and parameter review.

[stevec]

braking resistor(s) You can't just "add two" in parallel with some computation wrt the min resistance.

I'm presently struggling with my Huanyang VFD and it's "manual" and am making slow progress toward setting it up to run the original 3HP 3 PH 220V motor that I replaced years ago with a single PH 1.5HP motor on my TREE mill.

My question is, why can't one "add two" resistors in parallel to increase wattage (while halving resistance) or add them in series to double resistance value?

Maybe I just don't understand "computation wrt the min resistance."

[Long Tom]

Post the exact model number of the Hitachi VFD and I'll match a braking resistor(s) of some inexpensive type for you. You can't just "add two" in parallel with some computation wrt the min resistance.

It's dead easy to add the external pot and switches for your Hitachi. The vfd keypad or remote keypad is really only for data entry and parameter review.

Lakeside,

It's a Hitachi WJ200, 7.5kw 200V 3phase

I'm told that's a 10HP unit that gives 5 HP when derated to run off single-phase input voltage. And in fact, it's running my 5 HP Whacheon very nicely.

[refinery mike]

Putting a heater overload block on the smaller motor would not put a switch in the power lines. the heaters would only switch of the low voltage control circuit which would be no problem. The starter however should not be put so as to break the power lines going to your motor. Nothing says you can not put the heater block ofter the VFD and the starter before the VFD.

[refinery mike]

I work with VFDs constantly at work, and believe me the manuals are mind numbing. each one having hundreds of parameters that need to be set. And then just when you finally get to understand what is going on, they discontinue that model and ship you the new and improved model. With a whole new set of set up parameters.
I just got another one this week. Parameters number into the 400s. Makes you want to scream.

[lakeside53]

braking resistor(s) You can't just "add two" in parallel with some computation wrt the min resistance.

I'm presently struggling with my Huanyang VFD and it's "manual" and am making slow progress toward setting it up to run the original 3HP 3 PH 220V motor that I replaced years ago with a single PH 1.5HP motor on my TREE mill.

My question is, why can't one "add two" resistors in parallel to increase wattage (while halving resistance) or add them in series to double resistance value?

Maybe I just don't understand "computation wrt the min resistance."

You can series or parallel resistors, but the VFD will have a MINIMUM resistance, and the resistance chosen determines the max available duty cycle. "Resistance " determines the current though the chopper, and that has an internal heating effect. The internal choppers (IGBT or FET) have to be protected for overload. Lower resistance gives greater braking effects, but at the cost of lower duty cycle. A quality VFD will have protection from longer term thermal overloads (duty cycle exceeded) but adding too low a resistance will often just burn them out.

[lakeside53]

Putting a heater overload block on the smaller motor would not put a switch in the power lines. the heaters would only switch of the low voltage control circuit which would be no problem. The starter however should not be put so as to break the power lines going to your motor. Nothing says you can not put the heater block ofter the VFD and the starter before the VFD.

The vfd is a rated motor starter, so adding any form of overload protection before it other the recommend fuses or breakers is not advised.

[lakeside53]

Post the exact model number of the Hitachi VFD and I'll match a braking resistor(s) of some inexpensive type for you. You can't just "add two" in parallel with some computation wrt the min resistance.

It's dead easy to add the external pot and switches for your Hitachi. The vfd keypad or remote keypad is really only for data entry and parameter review.

Lakeside,

It's a Hitachi WJ200, 7.5kw 200V 3phase

I'm told that's a 10HP unit that gives 5 HP when derated to run off single-phase input voltage. And in fact, it's running my 5 HP Whacheon very nicely.

Here's the data you need (nice of them to leave it out of the manuals).

http://www.hitachi-america.us/supportin ... _Table.pdf

Your vfd has a decent capacity braking unit, but still limited in duty cycle.

Two extremes :
At minimum resistance of 17 ohms, you can get 80% braking torque at 10% duty cycle. That's 1 minute of braking per 10 minutes of usage. Braking is way less than minute per instance so it's not as bad as it looks. Also, that's 80% of the 10hp torque, so 160% for your 5hp.

If you wanted to brake at 100% duty cycle (like repeated stopping and starting big inertial mass), you are limited to 54 ohm and 30% braking torque (60% of 5hp).

Take care with "cold" verses hot resistance (which is why you can't use light bulbs).

For general lathe work, I'd tend toward the lower resistance and program the vdf to limit any excess in duty cycle usage.

So... a typical 300w 120v heater (like an engine block heater) is about 48 ohms. So yes, you can put two of these on YOUR vfd as it can handle the 24 ohms but you won't get max performance (it will still be pretty good though). The car heaters usually have a fusible thermal link inside - rip that out. Put the block heater(s) on a heat sink with thermal grease.

720 watts at 120v is 20 ohm, so 120v heater elements in the 700-850 watts range will suffice.

Or you could just use a 240v 3000 watt water heater - that's 19 ohms. Many choices.... 1500 and 3000 watt (240v) stove elements are a great and cheap way to go. Don't get mislead by the likes of the cheap 300w "cup" heaters - they will simply overhead and burn out - designed to be in water and only for short periods. You could put a larger immersion heater in a few gallons of water if you like.

Couple of these in parallel at say $50 each would work nicely : http://www.ebay.com/itm/IPC-Post-Glover ... 258845c693

These two in series (great price) : http://www.ebay.com/itm/IPC-Post-Glover ... 258845c693

Many others on Ebay.


For low'ish braking cycles with reasonable inertial loads you only need about 100 watts per hp, so 500 watts or more will be fine for you. If you use a stove element or whatever, put it in a steel mesh box and allow plenty of airflow.

Keep your wires from the vfd to the braking resistor short, away from input and low voltage wires, and 12awg min. And.. keep your fingers away; 380+ DC volts on the terminals...

[ctwo]

I'll likely need a VFD 101 course soon, will be looking to power a 2HP bridgeport from 220V single phase. I was going to go with a 3HP rated 3/1 phase input TECO, due to price being about half that of the Hitatchi (and ironic that the single only phase is more expensive). Should I derate a single/three phase input model by two even though is it rated for either input, and thus look for a 4HP? This would be for a CNC, so either more favorable to run with Mach3 or LinuxCNC?

I'll have to read more into the details about the heater...