building a grinder

[vbottles]

Six foot is still really close. My garage has fine dust from grinding pretty much everywhere. I bought as big a box as I could get from wilko's (£15?). Or pony up and buy a proper ip66 cabinet.
Keep all edges aligned to help with tracking. I guess you have seen the links on British blades?
Andrew

 

[Depaugie]

Ii also intend to use it to power my mill using the 1.5hp motor,the mill is a baby mikron f75

how do you intend to power both mill and grinder via change-over switch?

 

[Depaugie]

I have the VFD mounted inside my grinder.
The motor's cooling fan blows past the heatsink and out that curved vent on the bottom.
3 years hard work and no probs so far.

 

[squazy84]

She's a beautiful machine well done!

 

[squazy84]

I'll just change plugs to switch between machines everything will be portable to an extent

 

[squazy84]

I can actually keep it in another room and pass the cable through the walls,I'm safe enough on the dust front as I'm well aware how fragile inverters are and how much dust gets everywhere,it will eventually have extraction on the grinder when I get that far

 

[squazy84]

interesting. ive built a few keep the pictures coming on build

Any pictures?

 

[brightspark]

your only-

Any pictures?

i have but there on me old computer il take some fresh ones and -post

 

[squazy84]

any ideas where to buy a 10 '' rubber coated contact wheel for this machine? or will I have to make my own?

 

[eddie49]

Take care when "changing plugs to switch between machines". I think that normally inverter outputs must be hard-wired to the motor, with no switchgear in between, so make double sure that the mains input to the inverter is off before you change over the motor plugs.

 

[Depaugie]

Take care when "changing plugs to switch between machines". I think that normally inverter outputs must be hard-wired to the motor, with no switchgear in between, so make double sure that the mains input to the inverter is off before you change over the motor plugs.

I was thinking about that!
I have a 3 kW motto in both my lathe and mill.
At the moment they share one VFD via changing a 4sq fly lead- messy.
I was pondering using a 65amp change-over switch, isolating the VFD first or forking out another 200squids for a second unit.

 

[Maker]

Provided the VFD is not providing any power when it is unplugged/switched it will be fine.

 

[squazy84]

It wouldn't be like me to unplug it running in any case,but what are the possible effects?

 

[MattH]

100% destroyed VFD.

 

[squazy84]

Surely such a box of electronic wizardry has a safety for such an event,according to the manual it can do turn water into wine lol

 

[eddie49]

A motor is a big inductor, and disconnecting under power would produce a voltage spike, which the output transistors of the VFD won't like.
Apart from plugs and switches, another thing that VFDs don't like on their output side is long cables. The cable from the VFD to the motor should be short, shielded, and the shield grounded ( since the 3-phase AC nominally at 50 Hz is actually a pseudo waveform, pulsing at up to 20 kHz ). A lot of VFD handbooks recommend mounting the box close to the motor.

 

[squazy84]

turning my shaft down for the pulley on the grinder (toy myford ml10)
new toy landed,so pleased with this little thing!

had to try it out lol

 

[squazy84]

anyway after sufficent playtime i got back on track a small bit
im sure this inst how its supposed to be done but its how im doing it!

shaft fits pulley and bearings anyway

then i got my set screws ect


I cut the keyway with the little mikron mill,first time cutting a keyway and the mill was easy to use and get a good fit

 

[Depaugie]

Looking good.
you are going for an indirect drive thru motor, belt and pulley.
If you haven't got your motor yet, you might consider a direct drive + controller.
Save all the messing about with pulleys and changing speeds the hard way.

 

[squazy84]

im driving indirect and using variable speed via vfd powered 3 phase motor,its my own preference, im sure it wont make sense to some but i prefer not to have to load up a motor with a belt wheel and down the road i may change power source more easily this way,i also like the rigidity the bearing carriers give to the design