J&S 540 surface grinder question

Anyone out there have a J&S 540, am wondering how freely the wheel spins when not under power.

Hi Alan, if you take off the belt at the back behind the cover the spindle should spin freely and for quite a time depending if you have a wheel mounted or not and wheel size. Evan with the belt on it should spin freely without any noise unless the motor bearings are shot. When you turn off the power it should slow down slowly not abruptly.

David

The older ones with plain bearings used a wick-fed system to keep oil flowing to the spindle. The oil was flung up into a reservoir and drained down a gallery to the wicks. These type won't turn as freely as the bearing spindle types and they will be heavier to turn until they have been warmed up before use.

Thanks for the reply’s.......when i first got the machine i powered up the head and it spun up no problem, however the head was virtually dry as the oil level sightglass was broken and the oil was thick and filthy

So now iv’e cleaned the machine up a bit, changed the hydraulic oil, replaced the sightglass and put fresh oil/kerosine in the head, removed the table and cleaned out the oil feed holes etc.

Also manouvered it tight against a wall ( A pig to move) and levelled it up with shims.

I tested it yesterday and the spindle motor seemed to be having trouble starting, Lots of humming and sparks coming from the contactor, so i stripped out the contactor, cleaned up the contacts and away it went.

Played about grinding things for approx an hour to get a feel for the controls etc. The head was just warm, not hot. Turned it off and then tried to restart, but no chance. Wired the motor direct and it still wont spin up, it just hums.

The spindle feels tighter than i would have imagined, so am guessing either spindle is tight or motor bearings are shot. Was trying to avoid having to move the machine again, but motor and belt access is from the rear, so looks like i will have to.

Something else im not sure about too. The oil catching resevoir tube in the head had another tin split tube clipped over it, which seems to defeat the object as it would stop oil from getting caught in the trough and looks a bit home made......Any ideas ? See pics

I believe that the plain bearing heads are supposed to run surprisingly hot. The motor problem sounds as if you may have lost a phase to the motor. Check the continuity of each phase of the motor windings.

Just looked up my J&S 1400 instruction book. That says that the normal running temperature for the plain bearing head on that model is 60°C !

Thanks Mark, think i’m going to pull the grinder out from the wall at the weekend and investigate further. Was hoping a clean up and service was all it needed, but that seems not to be the case..........bugger

Well a bit more progress......Sort of

Pulled the drive belt off and both motor and spindle spin freely. (Phew!)

Tried running the motor with no belt on and it works fine. So happy that motor is ok.

Think the issue is my RPC can’t supply enough initial current to spin the motor up with the belt on, the load must just be too high.

Strange really as the RPC idler motor is 3hp, and nothing bad is happening inside the RPC cabinet, no blown fuses, nothing getting hot etc.......Grinder motor just growls and the note of the idler motor changes to a stressed tone.

So guess i need to build a bigger RPC, 5 hp maybe, Don’t really fancy the inverter route for this machine, as there are potentially 3 motors running when the vac is on.

Never simple is it