2.8 Connection of stand-alone option units The inverter accepts a variety of stand-alone option units as required. Incorrect connection will cause inverter damage or accident. Connect and operate the option unit carefully in accordance with the Instruction Manual of the corresponding option unit. 2.8.1 Connection of the brake unit (FR-BU2) Connect the brake unit (FR-BU2(H)) as follows to improve the braking capability during deceleration.
Connection example with the GRZG type discharging resistor OCR contact OFF ON MC T *2 MC OCR GRZG type discharging resistor *5 Three-phase AC power supply MCCB MC R/L1 S/L2 T/L3 U V W Motor External thermal relay R R IM *4 Inverter PR *3 FR-BU2 P/+ N/- P/+ A *1 N/- BUE SD *3 *1 When wiring, make sure to match the terminal symbol (P/+, N/-) at the inverter side and at the brake unit (FR-BU2) side. (Incorrect connection will damage the inverter and brake unit.) *2 When the power supply is 400 V class, install a stepdown transformer. *3 The wiring distance between the inverter, brake unit (FR-BU2) , and discharging resistor must be within 5 m.
Even when the cable is twisted, the wiring length must be within 10 m. *4 It is recommended to install an external thermal relay to prevent overheat of the discharging resistor. *5 For the connection method of the discharging resistor, refer to the Instruction Manual of the FR-BU2. • Recommended external thermal relay 1/L 1 5/L 3 2/T 1 6/T 3 To the brake unit terminal P/+ To a resistor • Set "1" in Pr.0 Brake mode selection in the FR-BU2 to use a GRZG type discharging resistor. 42 2.
INSTALLATION AND WIRING 2.8 Connection of stand-alone option units C 10 m or less Brake unit Discharging resistor Recommended external thermal relay FR-BU2-1.5K GZG 300W-50Ω (one) TH-T25-1.3A FR-BU2-3.7K GRZG 200-10Ω (three in series) TH-T25-3.6A FR-BU2-7.5K GRZG 300-5Ω (four in series) TH-T25-6.6A FR-BU2-15K GRZG 400-2Ω (six in series) TH-T25-11A FR-BU2-H7.5K GRZG 200-10Ω (six in series) TH-T25-3.6A FR-BU2-H15K GRZG 300-5Ω (eight in series) TH-T25-6.6A FR-BU2-H30K GRZG 400-2Ω (twelve in series) TH-T25 11A NOTE