Hi Gareth, you do not mention which type of M300 you have purchased or are purchasing.

I have the same later (2003) white model that Ken Wilson covered in the MEW no.154 -2009. These models have more extended electrical controls than the cream coloured earlier versions. There are more contactors and overload protectors to deal with.

I found Kens version really good but overly complex on the logic controls. I hence did my own circuit diagram on the CAD with a lot of help from a friend who is an electrical wizzard and got him to check it all as i progressed. All the contactors and overload protects are done and supplemented as in Kens circuit but my logic controls differ but still retain all the use of all original controls and safety features.

I do have the coolant pump in the circuit which worked when i tested it but i never use it. I use a none soluble cutting oil from a Wurth oil spray application bottle. I find this far more userfriendly to the machines slideways etc.

I use the Teco inverter which to date has been perfect. I do have an issue with the foot bar brake. It works as normal if not used too heavily but under total emergency hammer down braking it decelerates the inverter too quickly and throws an error that needs a total repower to clear. It does do the dramatic stop that may be needed. This is because it also uses break blocks on the pully alongside the inverters electrical breaking. At the moment i live with this but may be future work in progress as i dont normally use the foot brake as the saddle lever controls work very well on their own. I know the foot brakes is there if i need it in an emergency.

You do need to Joint the yahoo harrison lathe user group as there is masses of info on there on VFD,s and their application and highlighted potential problems that have been overcome. There is a user on there called Rupert Powell who has provided invaluable info and drawings, some of which I have incorporated into the logic part of my controls.

Gareth, PM sent. As regards rapid shut down of inverter under E foot brake use, I have a minor mini red button that does the reset.

MalcB.

May I reply to your "but overly complex on the logic controls" ?

I merely removed from the original Harrison circuit, those items not necessary for the Inverter approach. I kept otherwise to the Harrison logic approach to controls and safety. I could with a minimum of work, revert to the 3 phase power without the inverter.

Ken Willson

Gareth,

Not a problem, VFD hardly notices it.

MalcB,

The chuck guard limit switch/wiring lies at the base of the left hand pedestal, unused but still wired. I hate chuck guards in general but the M300 one has a use to hold the horribly heavy extra large 4 jaw ind when fitting/removal.

K

Tape it closed, remove and leave tied up, first thing i did 8 1/2 years ago.

I run an invertor and can run the rotary just a simply pull plug out of invertor socket and put in the rotary socket and switch on. Both run through control panel incliding isolator, many contactors and on/off switch.

Did buy a Mitsubishi D720 2.2KW 220V 3PH cheapy and filter last year but cant afford the down time to install and figure out. D720 are not dust proof and need to be enclosed and in reach.
Need another vfd for the coolant pump about £50.

My M300 is an English one and have no use for variable speed they have a brilliant gearbox like all other Harrisons and Colchesters. Only reason want the vfd on is i have supply problems plus limited to 65A input and to compare all three power sources Rotary, Digi Invertor and a decent VFD running 220v.