Solenoid valve question

[scrambled]

I am trying to fix some problems with the MHP mill that I bought.

The solenoid valves are leaking around the valve and the manifold gasket. I tried to clean and repair the gasket, but it looks like the gasket and the hold down lock are damaged.

So I am planning on replacing the valves. When I started checking the voltages for the coil, I found 2 that are 110 volts ac, and three that are 24 volts dc.

I have three that are three that are double ended, and two that are single ended.

All the valves are driven from relays, so it SHOULD be easy to change all the valves to one voltage.

Is there some reason that this was done that I am not aware of? The valves control tool changer in and out, tool changer up and down, hi / low gearbox control, chuck open/ close and air blow for the chuck.


I found these valves on e-bay

SMC 6 Station VS7 Series Valve Assembly VS7-6-FG-D-3Z-Q - eBay (item 390212868108 end time Dec-20-10 13:40:52 PST)

any ideas?


Thanks for the help.



Steve

[Al_The_Man]

As a general rule, DC solenoids are superior to AC, If an AC solenoid does not completely shift the spool over the coil is liable to burn out, also if someone pushes a plunger over manually of a double coil valve while the opposite coil is picked up, it will also burn out or blow a fuse.
This does not happen on DC solenoids.
Al.

[scrambled]

Thanks Al


I will order the e-bay valves later tonight.