Eaton S811+N37 series User Manual

Contents

Installation18 S811+ Soft Starter MN03900001E—November 2012Using Auxiliary ContactsOften these contacts are used as shown in the illustrationson this page with indicating lamps. In some installations theuser may wish to use an electromagnetic relay for indicationof the status at a remote location for use by a programmablecontroller (PLC), or in a 120 Vac control circuit.If the S811+ Soft Starter is subject to mechanical shockduring operation, it is possible that these contacts maymomentarily open, causing nuisance fault tripping of downstream devices. When used with an indicating lamp, amomentary contact opening would not be observed. In orderto assure proper application, it is suggested that thefollowing recommendations be implemented:PLC Interface—It is suggested that a 20 ms delay beprogrammed to assure the contact status before a change ofstatus is indicated. The application and the environmentalissues will determine the exact requirements.120 Vac Signal Control—When a relay is used inconjunction with an electronic control, it is highlyrecommended that a noise suppressor be used across therelay coil. In the case of an AC coil, the noise suppressor ismade up of a series connected resistor and capacitor asshown in the figure below. Usually the delay in the relayopening is very small, so if the system is subject to shock, adelay should be added in the external control before thecontact change of state is recognized. The resistor is rated100 ohms at 0.5 watts. The capacitor is 0.25 μF at 250 Vac.120 Vac Control24 Vdc Signal Control—When a relay is used in conjunctionwith an electronic control, it is highly recommended that anoise suppression/snubber diode be placed across the relaycoil as shown below. This diode offers two benefits. First,the suppression of any electrical noise generated when therelay coil is de-energized. Second, the diode delays theopening of the relay slightly as it dissipates the energy storedin the relay coil. This delay is often long enough tocompensate for the potential effects of a mechanical shockopening the control contact. A typical suppression diode is a1N4001.24 Vdc Control–+1314959698BypassReady120V ACSupplyFaultRRR–+1314R959698BypassReady24V DCSupplyFaultRR