Download brochure - Renold plc

Page 65Overload Protection321628LL150.841.01101442818.5When a hydraulic coupling experiences overload there is acorrespondingly high slip value accompanied by a rise in the oiltemperature. To prevent damage to the drive there are threeoptions available.1. Fusible plugThis is fitted as standard on all HydraStart couplings sizes 4 andabove. The standard plug is set to fuse at 138°C. Another optionavailable allows fusing at 183°C. Because oil is discharged whenthe plug fuses it is advisable to correctly guard couplings usingthis type of device.2. Thermal triggerFitted as an option on HydraStart couplings sizes 6 and above,this device prevents oil being discharged from the coupling atoverload. As with the fusible plug, two melt temperatures areoffered. When melt point is reached a pin is released whichengages with a limit switch. The signal from this switch canoperate an alarm or switch off the electric motor to protect thedrive. After the cause of the overload has been removed thedrive can be restarted after replacing the thermal trigger.HydraStart thermal triggerSize A L LiHS6 345 93.7 21.5HS8 422 123.2 20.0HS10 511 146.1 16.0HS11 580 144.5 10.5HS12 669 173.3 10.5Operating principlesThis device will trigger the limit switch if the oil temperaturereaches a predetermined level without loss of oil from thecoupling. Fusible trigger plug 117°C alternatively 138°C.Electrical characteristics2-Pole 1N/C + 1N/O, conforms to IEC 529 IP 66, contact typeXCK rating 500V AC-153-20mm ISO Cable Entries.3. Non-contact sensorNon-contact speed and heat sensors can be supplied which shutdown the drive in the event of overload. Please contact Renoldfor more information.www.renold.com