Power Electronics Motor brake relay GA 90 ministop 0 Thyristor electronic brake relay for motors up to kw Adjustable braking current up to 0 A Adjustable braking time Automatic standstill monitoring (optional) Alternatively with reduced braking delay time (0 ms) Protection against overtemperature (optional) Width 9 mm Function diagram Approvals and marking U B L-L Q-Q 7-8 7-8 I B t+t+t = braking delay time tb = braking time Circuit diagram t t t tb L L Q 7 7 M78_a t Applications woodworking machines centrifuges, conveyor belts mills, grinding machines shaker conveyors Construction and action With the supply voltage connected to terminals L-L, the interlock contact 7-8 for the motor contactor is closed. A red LED indicates that supply voltage is present. The motor can started by "ON" button. The DC braking current can be collected at the T and T terminals. The external braking contactor is triggered by the contacts 7-8. Through stringent timing of the braking sequences (safety times) the braking contactor is prevented from closing until the motor start contactor has opened and that induced voltages have decayed to a safe level nondestructive to the power electronics. The relay operates in the following manner: When the motor contactor has been deenergized, the braking current contactor is closed, after a fixed safety time delay to allow inductive voltages to decay. After that the braking current is flowing through the stator windings for the set braking time. T T Q 8 8 T T PE L L 7 8 7 8 Q Q M77 Circuit diagram only for GA 90/ Indicators LED red (L/L): LED red (J): LED green (I B ): Notes supply voltage is present thermal protection has responsed braking current is present Because the DC braking current is produced by a phase controlled thyristor rectification circuit and the DC current is a product of the supply voltage applied to L-L and the winding resistance, the max. current can be singnificantly larger than the permissible current, if the potentiometer is turned to right end. All technical data in this list relate to the state at the moment of edition. We reserve the rigth for technical improvements and changes at any time. GA 90 /.0.0 d
Technical data Input Nominal voltage L, L: Voltage range: Nominal frequency: Nominal consumption: Output AC 0, 0, 00,, 0, 00 V 0,8..., U N 0 / 0 Hz VA Contacts: NO contacts Rated motor power at 00 V: 7, kw / kw / kw / kw / kw Braking current adjustable: A / 0 A / 90 A / 0 A / 0 A Braking time: 0 s, 0 s, 0 s, 00 s, 80 s ± 0 % Braking delay time: 0, s / 0, s / 0, s / 0,8 s /,0 s Switching capacity of the monitoring contacts to AC : A / AC 0 V EN 0 97-- Fuse, superfast: 0 A / 80 A / A / 0 A / A Mechanical life: 0 x 0 switching cycles EN 0 97-- Wire connection Power module solid wire (mm ): / / / 0 / 0 stranded wire (mm ): 0 / 0 / 0 / / Control unit:, mm solid or, mm stranded ferruled General data Temperature range: - 0... + C Storage temperature: -... + 70 C Clearance and creepage distances overvoltage category/ contamination level: kv / IEC 0 - EMC Electrostatic discharge: kv (air) EN 000-- Fast transients: kv EN 000-- Surge voltages between wires for power supply: kv EN 000-- between wire and ground: kv EN 000-- Degree of protection: Housing: IP 00 EN 0 9 Terminals: IP 00 EN 0 9 Housing: Thermoplastics with V0-behavior Vibration resistance: according to UL Subject 9 Amplitude 0, mm, frequency 0... Hz EN 0 08-- Mounting: screw fixing 7 x 00 mm DIN Weight:, kg /, kg /,9 kg /,9 kg /,9 kg Dimensions Width x height x depth: Standard type 9 x 9 x mm GA 90 A 00 V AC 0 / 0 Hz 0 s Article number: 00 Thyristor electronic motor brake relay up to 7, kw Nominal voltage U N : AC 00 V Adjustable braking time up to 0 s Width 9 mm Variants GA 90/ : Temperature monitoring of the power rectifiers GA 90/ : Standstill monitoring by proximity switch GA 90/ : automatic standstill monitoring GA 90/ : automatic standstill monitoring and Temperature monitoring GA 90/ : voltage free temperature contact - (NC) GA 90/ : multiturn potentiometer for setting of the braking current Variants GA 90/00: Ordering example for Variants Control input If the connection between Q-Q is made, the device turned into standby mode. After opening the connection, the device starts with braking. Monitoring output 7, 8: interlock contact for motor contactor 7, 8: activation of braking contactor contact rating AC 0 V / A Adjustment facilities Poti Description Fundamental adjustments I B braking current left position t B braking time mid position Commissioning The exact braking time t B has to be determined by trial. Braking current I B should be adjusted to,8 - times the rated motor current I N. If the motor stops and still hums time t B is too long. If motor still turning after time t B has elapsed, t B is too short and has to be increased. In the principal connection braking current I B is injected into one stator winding. For high inertia applications braking current I B should be injected into two or more stator windings. Braking with braking time t B and current I B Normal version GA 90/: _ As soon as circuit breaker S0 opens it is detected by the GA 90 via voltfree inputs Q-Q. After a fixed delay (depending on max. current) the braking current is connected for the time t B, contacts 7-8 are open to prevent energization of the motor contactor during braking. A lit green LED I B indicates that braking current I B is flowing. After t B has elapsed I B is switched off, contacts 7-8 close. The motor can be restarted. Braking with standstill monitoring GA 90/, GA 90/ braking delay time 0 ms, trigger unit for short circuit contactor, to eliminate inductive voltages GA 90 / _ 0 A AC 00 V 0/0Hz 0 s Braking time Nominal frequency Nominal voltage Max. braking current Variant, if required Type Depending on the mode of operation, the coil resistors of the stator coil are heating and the braking current ought to be readjusted again and again in order to achieve optimum braking. This can be excluded by monitoring of the standstill. The type variants GA 90/ and GA 90/ are provided with an automatic standstill monitoring facility requiring no additional sensors. For these devices, the braking current I B transformed by a current transformer generates a proportional voltage on a load. This voltage increases abruptly in the moment of motor standstill, and the motor braking device interprets this as a criterion of stop. Such automatic standstill monitoring guarantees the disconnection of the braking current at motor stop after a short delay time (< s). As an additional security the braking time is running as safety time, starting with the braking procedure and stopping the latter after run-off, in case the braking procedure has not been stopped by the standstill monitoring facility.
Commissioning Overtemperature protection GA 90/, GA 90/ It is possible under very arduous operating conditions that the relay power components will overheat. A thermal cut-out will disconnect the brake relay and by opening contacts 7-8 prevent reenergization of the motor until a suitable cooling period elapses. A red LED (J) indicates the overheat condition Response temperature: 90... 9 C Hysteresis: ca. % Safety instructions - Never clear a fault when the device is switched on - The user must ensure that the device and the necessary components are mounted and connected according to the locally applicable regulations and technical standards - Adjustments may only be carried out by instructed specialist staff, while the applicable safety rules must be observed. Characteristics Diagram to determine the load factor Note on dimensions When selecting a motor braking device the following points should be borne in mind: - Nominal motor current - Duration of operation (SD) - Ambient temperature - Type of circuit (number of stator coils acted on by braking current) For optimum braking power the braking current I B should be max.,8 - times the nominal motor current. This corresponds to the saturation current of the magnetic field required for braking. Higher current leads only to thermal overloading of the motor. Increased braking power is obtained by braking via two or more stator coils. The permitted duration of operation is determined by the braking current, the ambient temperature and the design of the instrument. Example: Nominal motor output: 0 kw Nominal motor current: 9 A Operating voltage: 00 V Ambient temperature: C Braking time: s The precise braking time must be established experimentally. Result: Optimum braking current Instrument design selected,8... I N = 0... 8 A GA 90 / 0 A The calculated braking current of 8 A, the selected ambient temperature of C and the right-hand quadrant of the load characteristic diagram give a maximum permitted load factor of %. Taking seconds as the braking time, the left-hand quadrant of the load characteristic diagram gives an operating cycle of seconds duration. The load factor ED (%) is the ratio of braking time t B vs. total cycle time SD t ED = B x 00 % x 00 % = = % SD With a lower ambient temperature the load factor can be increased. The make-to-break ratio is calculated from the braking time (t B ) and the rest time (t r ) t = B s = = : t r 0 s The rest time (t r ) is the difference between the operating cycle (SD) and the braking time (t B ). t r = SD - t B = s - s = 0 s
Application example Basic circuit for GA 90 / additional potential free contact to interlock the motor control in the case for overtemperature (only for GA 90/ ). S0 = Off K = brake contactor SI = On F = fuse = motor contactor L L L N F F on S A A L L Q off S K K GA 90/00 I> I> I> K Q Q T T K K K K K K K U V M W Basic circuit for GA90/00 with reduced braking delay time M78_a = main contactor K = braking contactor K = short circuit contactor K = interlock/activation of short circuit contactor K = activation braking contactor Basic circuit for GA 90/00 with reduced braking delay time
Application example Y - D - Control, braking with GA 90
N off slow on on fast F0 F F S0 SI K8M KT K8M slow timer star delta fast braking 7 7 8 8 Q Q L GA90 F L L T L K9M K9M KT K9M K8M K8M T K K K9M K8M U V W F L L L 97 9 F F 98 9 U ~ Y V M W PE U V W 97 9 98 9 M78_ Application example SII SII Dahlander control circuit with Y - D - start, braking of low and high revolutions with GA 90 E. DOLD & SÖHNE KG D-78 Furtwangen e-mail dold-relays@t-online.de internet http://www.dold.com Postf. Tel. +9 77 0 Telefax +9 77