Re: Rosta Motor Mount Misapplication
It's always worth remembering with these things that the line of action between the two pulleys cannot go through the centre of the ROSTA unit, or it cannot generate the lever-arm action necessary for tensioning.
The solution is usually to offset the ROSTA unit to allow it to pre-tension the belts and give the motor room to move along with the screen.
In applications where the driven shaft is oscillating relative to the motor shaft, it is also a good idea to oversize the ROSTA mount by one size. This gives the motorbase extra reserve capacity to allow the motor to move with the driven shaft, maintaining tension and minimising overload on the bearings. ■
Regards, Brett Holmes Crushing and Mining Equipment pty ltd ph +618 9437 1477 fax +618 9437 1577
Rosta Motor Mount Misapplication
Had an interesting story from the field this week.
Customer installed Rosta motor mount to replace pivoted motor mount on a ROD-SUSPENDED DILLON vibrating SCREEN
The original motor was mounted on the suspension frame at 12 oclock position above screen drive sheave. The belt alignment on the original setup was straight up and down. The replacement ROSTA motor mount was installed on an angle of plus/minus 5 degree from horizontal on a separate FLOOR mounted frame off the structure.
Problems created included: DAMAGE to screen box & components
1. The belts now pulled the rod suspended system COCKED hard towards the feed end of the screen box.
2. Screen box is now sitting NOT FREELY on the rods, but HARD against the GRAPHITE GUIDES in restriction vs free hanging.
3. The graphite guides which sit in cast holders were torn up and the cast holders were CRACKED
4. The coil springs broke at the bottom turns, due to vibrating in a non straight up and down position now (leaning)
4. A bearing change was done at time of repair - the drive setup was now pulling the drive up towards the feed end of the screen box and was running the bearings in restriction vs true due to the motor mount installation position.
5. REPAIR list included: new coil springs, new graphite guide rubbers all corners, new holders all around, new drive assembly and relocation of the ROSTA motor mount to the 12 oclock position to simulate the original drive setup.
PROBLEM: Drive was located in the wrong position, not taking proper consideration of original setup.
PIC on the next post. ■