Toshiba VF-A7 When using a braking resistor without thermal fuse,  PBR resistor capacity

b) When using a braking resistor without thermal fuse

＊If no power supply is provided				External	braking resistor
		THR		(optional)
	for the control circuit
ＭＣＣＢ	ＭＣ		ＰＡ	ＰＢ
Power		Ｒ		Ｕ	Motor
		Ｓ		Ｖ	IM
supply
		Ｔ		Ｗ
	2:1
	(*2)		Inverter	Ｆ	Forward/stop
	ＭＣ	ＦＬＢ		Ｒ	Reverse/stop

	(*1)	Fuse	Surge killer
Power			ＦＬＣ	ＣＣ
	ＴＣ

supply ＦＬＡ Ｇ/Ｅ

(*1)		Connection when using an MCCB with a top coil instead of an MC.
(*2)		A step-down transformer is required for 400V models but not for 200V models.
	[Parameter		setting]
		Title	Function	Adjustment range	Setting value
			Dynamic braking	: Disabled	
			mode selection	: Enabled with over load detection
			PBR resistor	～ [Ω]	Any value	(*3)
			PBR resistor capacity	～ [kW]	Any value	(*3)

(When the standard internal braking resistor option is not used, be sure to set the parameters F308 and F309 properly for overload protection.)

(*3)  is for overload protection of our optional PBR and PBR3 type. When DGP type is used, set  = 600 kW and protect the circuit by external thermal.

※A thermal relay (THR) must be connected as the last resort for fire prevention in case a failure occurs in the overload and over-current protective functions provided for the inverter to protect the braking resistor. Select and connect a thermal relay (THR) with a capacity (watt) commensurate with that of the braking resistor used.

- Caution -

In the above circuit, the MC in the main circuit is turned off if an inverter's protective function is activated, and consequently no trip message is displayed. The inverter recovers from a trip if it is turned off. So, check the trip history record after turning off the inverter and then on again. (Refer to 8.1.)

To prevent a trip condition from being cleared by turning off the power and then on again, change the setting of the inverter trip retention selection parameter F602. (Refer to 6.25.3)

＊Control power unit option（22kW or less）

ＭＣ

Ｒ

Ｓ 22kW or less Ｔ Option

Ｒ０

Ｓ０

In a circuit where a control power supply is connected to RO and SO, when the MC in the main circuit is turned off when a trip is occurred, trip data is saved so that trip messages can be displayed (FL output also is retained.) For optional control power supply units, refer to 9.4.

When using a custom braking resistor, be sure to select a braking resistor with a resistance larger than the minimum admissible resistance. Refer to 4 on the next page for the minimum admissible resistance.

F-27