Thread: Huanyang VFD issue when engaging lathe clutch

Originally Posted by Michael G

If you are using IE there may be issues as there have been before.
(try toggling the compatibility or better yet, use something else)

Michael

Thanks for that Michael, I'll try Chrome.

Phil

PS: judging from my next post it seems to have fixed it, great.

Originally Posted by philbur

You can also mechanically reverse the spindle direction with lever B, so if you use your ammeter you can maybe determine if the issue is mechanical and not electrical.

Phil

Also if you slacken the drive belt by raising the motor using the jacking screws inside the end cover, and position lever B in the middle, the pulley should rotate freely on its bearings separately from the spindle. You should be able to feel if the pulley bearings or anything else is binding. The only point of fixed contact between the pulley and the spindle is the drive gears to the right hand end.

The righthand bearing is feed with oil from the drive gear reservoir. The left pulley bearing is feed with oil via the oil nipple on top of the left plain spindle bearing housing. It is possible to refit the pulley assembly with the oil port in the pulley miss-aligned by 180 degrees. So if it has previously been messed with ..................!

Phil

Originally Posted by philbur

You said previously:

“The reason for the VFD, is that I purchased a 5hp RotaryPhase Converter (Phase Changer brand) but it was bogging (running at max load)when I switched to high speed.”

This should not happen, I run mine happily on a 5hp RPC.It possibly suggests that you have mechanical problems. High speed (3500 rpm)needs special oil in the plain bearings and even then it’s possible they get toowarm and start to bind if things are not adjusted just right. You should give more information about thepulley bearing housing rotating 180 degrees as I mention in the other thread.This suggest some sort of binding which could result in high amps.

I tried some different gear settings today on the 5LZ. Running the 1:1 I am getting quite a lot of noise out of the rear of the headstock. I will likely have to pull it down as it does not sound right. What's more it is difficult to engage 1:1 and 1:4 in the headstock (lever B).

Any ideas on how to torque the spindle bearings?

Originally Posted by philbur

There is no instant, plug reversing, when you operate switch C.The clutch disconnects the motor and the brake stops the spindle, then the twoclutches together engage the 4 speed reverse after the brake has released. The motor never stops or reverse direction and the clutchesprovide a soft start which is less abrupt than starting the motor in eitherdirection from scratch.

Interesting that it is a "softer start" than starting with the clutch engaging reverse. I can start on high-speed with the reverse engaged (via clutch) and it spins up fine. If I however start with the brake engaged, then flick to reverse (via clutch) it trips the VFD. It seems like there is a lot more load by engaging the clutch than running from a stop with reverse engaged.

Originally Posted by philbur

Do the high amps continue when in reverse at high speed oris it just during spin up. The 4 speed reverse is for threading only so youshould not be doing this at high rpm. Forward threading should maybe be limitedto 200 rpm or so, which means reverse should not be more than about 800 rpm. Ithink you will wear out the clutches and the brake very quickly if you areperforming this operation at 2000 or 3000 rpm.

The high amps only exist during spin-up. As soon as it has got to a point of momentum the amps drop rapidly. It seems like it is that initial start that kills it. It has no problem when it succeeds (1 in 10 times), amps fall quickly.

It is not so much that I need this for threading. It's an integral part of the gearing for selecting various speeds. I guess I should really be starting the 5LZ with the Reverse engaged via the clutch, as apposed to starting with the clutch in the Brake position?

Originally Posted by philbur

You can also mechanically reverse the spindle direction with lever B, so if you use your ammeter you can maybe determine if the issue is mechanical and not electrical.

I did not try the ammeter, but did test this mechanically today. It results in the same issue. The VFD trips out. I had a couple of times where it worked, but mostly not.

At this point I think I have more a mechanical issue in the headstock. A previous owner has torn the machine down. I am finding this out the hard way. Every second bolt is loose. I poured some oil into the feedbox to find it dripping out on the floor . A previous owner had removed the bung but not replaced it!!

Even though the Huanyang willl protect itself from over current by tripping out I wonder how many times this can be done safely?

While I was setting up my compressor the 3kW 3kW Huanyang tripped ~20 times while ramping up, and it is still running fine.
On my Linisher which uses a 2.2kW 3kW Huanyang this happened maybe a dozen also still running fine.
On a cheap used (750W) VFD that I used on a grinder the caps blew after about half a dozen trips.
The same brand of cheap VFD (as used on a grinder) on a 1/4 HP blower. This one has tripped more than 20 times - still OK
The Linisher, Grinder and Blower all tripped when trying to decelerate too quickly or turning the speed down too quickly.

This problem has been fixed on the Huanyangs running the Linisher and grinder by lengthening the deceleration times but the blower has a minimum decelerate time of 1s so I just adjust the speed on that slowly. The blower typically runs on about 3 speeds slow medium and flat out so its no problem to adjust things slowly.

I'd be interested to know how many times trips have happened to other VFDs out there.

Originally Posted by BobL

.........
On a cheap used (750W) VFD that I used on a grinder the caps blew after about half a dozen trips
.......

When decellerating the motor acts like a generator and charges the DC bus capactitors. In doing so, the DC bus voltage rises. The VFD software will "trip" once a certain bus voltage is exceeded, stopping the breaking action and preventing the voltage to rise further. Depending on the software, several subsequent such "trips" without much delay in between may cause the voltage across the capacitors of the DC bus to rise higher than would be the case with a single trip.

Cheap VFD's use cheap DC-bus capacitors. These DC bus capacitors are expensive items, as you may have found out whilst trying to buy replacements. I have seen Chinese low cost VFD's using noname caps rated only 85 degreesC, whilst brand name VFD's use brand name caps rated two temperature classes higher. The price difference of the DC bus caps alone may justify 1/4 of the whole VFD price for a quality unit.

One more thing: if you use a VFD that was not running for a long time, like an "old stock" bargain, it pays off to gradually condition (or re-form) the bus capacitors using a variac. Applying a slowly increasing mains voltage to the VFD over several hours. This will prevent caps blowing, especially after a few braking trips.