New bandsaw

[woodpig]

VFD's aren't without issues. I've seen folks talk about inference with other equipment and also RCD's tripping.
Just one at random:

http://www.theiet.org/forums/forum/mess ... adid=35587

VFD's can be really useful in some applications providing variable speed, slow start and braking etc. but I'd still say don't buy cheap. Mitsubishi or Fuji may seem more expensive but could work out cheaper in the end.

 

[tomasg]

Hi again
I presume in N.Ireland that you have the regular type bog standard MCB circut breakers like most places down south from you
and not RCD's .
I was also very concerned about inference with other equipment ..... aka Phantom earth leakage
What i got from reading that the closer the VFD is to the motor the less noise /interference will happen
also done the recommended metal box to cover the VFD so thats more protection .
It seems that close proximity with high speed DC motors is the only concern with electrical equipment like ICD 's
All else ive read is that their might be some interference with an AM radio ..but i could not find any threads of that online
and have not experienced this myself
Complete novice here BTW (homer)
Has their been any recent cases of these Huanyang inverters breaking under normal conditions ????
Hope this helps

 

[graduate_owner]

I bought a Eurotherm inverter about 10 years ago and it worked fine (until last month) with no setting of parameters at all. I just connected the incoming single phase wiring to the terminals and the motor to the output and that was it. You must connect the motor directly to the inverter though, do not use any additional switchgear. Bypass the bandsaw on\off switch and control it directly from the inverter. You will get variable speed and reverse (reverse would be a fantastically useful thing to have on a bandsaw, I don't think,) but you could connect via a 3phase plug and socket and use the inverter for other machines where these features would be advantageous.

I agree with the comments about Far East products. When I replace my Eurotherm I will go for similar, or possibly Jaguar or Mitsubishi. Not cheap , and if you are thinking of using it for other machines in the future then obviously buy a model that has a high enough power rating for what you think you might need, which means spending even more, but as the wise people say - buy cheap buy twice.

K

 

[wizard]

My inverters are plug and go but when I fitted a remote switch I had to be talked through setting it up. It was not easy but the place I bought it from was very helpful. Also as already said you can NOT use any switch that is already on the machine.

 

[byrnsey]

Ok so heres what it says on the plate
Brown Euromotor Pestell IEC34-1,VDEOS30
Code A30121 No 030628-119
V 220-240 (triangle) - 380-420 (upside down Y) A 3/1 7
KW 0.55 RPM 870
PH 3 HZ 50 IP 55 CC F Rise B

Am starting to think id meybe be best to get a new motor for it, what yous think?? Thanks for the help.

 

[DennisCA]

Pretty weak motor, strange they'd put something so weak on a bandsaw that size. I'd go minimum .75kw but preferably 2.2kw or thereabouts.

Given the low RPM it sounds like its meant for a direct drive saw? Or is it connected via a pulley and belt?

 

[byrnsey]

I think its direct drive, the motor is right behind the bandsaw wheel, no sign of any pully or belt.

 

[DennisCA]

That explains the low RPMs then, it's probably an 8-pole motor. To find a new motor of such low RPMs might be difficult, or costly. You can't just put in any old motor with a different RPM, you need the same speed motor.

 

[byrnsey]

So is the bandsaw not really up to much then? Not sounding too good #-o

 

[DennisCA]

I dunno about that, if thats the factory motor the manufacturers obviously thought it was sufficient, seems weak to me though. I guess it'll be fine for most types work, but I think it'd struggle resawing. Plus side is an inverter for such a small motor is cheaper. I think that's the fastest way to get it up and running, then keep your eye out for a good deal on a used 1-phase motor of similar RPM, preferably 2kw+.

Being that small it could also be converted to 1-phase but you really can't afford to loose any more motor power so I would advise against that.

 

[byrnsey]

Sorry DennisCA, this might seem like a silly question but why cant i use a new motor with more rpm if the motor is connected directly to the wheel?

 

[DennisCA]

Well when the wheel is connected directly to the wheel shaft (my bandsaw is the same way), then it will turn with the exact same speed as the motor. So basically, it'd go too fast!

With bandsaws that use pulleys and belts you could take a 1400rpm motor (most common motor I think) and use a pulley ratio to reduce the speed of your bandsaws wheel to 700-900rpm, which is the range wood cutting bandsaws prefer. Though some go higher but thats not optimal.

So one has less choice of a motor with a direct drive bandsaw like you and I have, we can't swap pulleys and fiddle with gear ratios to get the correct speed. This is where some people use a VFD to control the speed of the motor but I've heard it's not good for the motors health to run it at less than it's rated RPM under load.

 

[tomasg]

Hi byrnsey
Found a youtube video that might be of interest
Its a 352 though
http://www.youtube.com/watch?v=OPRBmd_nvLU