System Protection; Asd Protection - Toshiba Q9 Plus Bypass ASD Installation & Operation Manual

System Protection

The Q9 Plus Bypass ASD/Q9 Plus Bypass Box has protection features that are designed to protect the
ASD and the motor from overload/over-current damage and from the undesirable effects of under-
voltage operation. Because of the different types of over-current conditions that may occur (i.e., inrush
current, short circuit current, extended overloads, etc.), the Q9 Plus Bypass ASD/Q9 Plus Bypass Box is
equipped to protect the system from start-up over-current and running over-current damage. Both
protection mechanisms require an application-specific adjustment to optimize performance and
minimize nuisance tripping.
There are two system operating modes: Q9 Plus Bypass ASD-driven and Bypass operation. When the
motor is being driven by the ASD, the primary over-current protection and extended overload
protection for the ASD is accomplished via the Electronic Thermal Protection setting of the ASD.
This parameter should be set to the FLA of the motor (see F631).
The power unit of the Q9 Plus Bypass ASD/Q9 Plus Bypass Box is rated for 100,000 Amps
Interrupting Capacity (AIC). The bypass circuit is rated for 100,000 Amps Interrupting Capacity also.
Overload protection for the Bypass mode of operation is accomplished via the Motor Circuit
Protector shown on pg. 18 and the Overload Circuit Protector shown on pg. 19 (both shown
schematically in Figure 7 on pg. 31).

ASD Protection

The Q9 Plus Bypass ASD/Q9 Plus Bypass Box is designed and manufactured to accommodate a wide
range of voltage and current requirements (typeforms). Each typeform is designed to operate at 100%
output continuously and can operate at 110% for up to 60 seconds. A trip will be incurred if the design
specifications are exceeded for a given typeform. Greater than 110% overload will have an inverse
affect on the overload time allowed.
ASD overload protection is accomplished via the ASD software which can be configured to disable the
system in the event of an overload. Using the Electronic Thermal Protection setting, the ASD may be
properly matched to the motor being driven and to the application (see F631).
The short-circuit protection, which is provided by hardware and software, disables the system in the
event of a fault.
The installer is to provide input fuses for the 230-volt Q9 Plus ASDs. The 460-volt Q9 Plus ASDs are
equipped with internal primary power input fuses as a standard feature.
When connecting two or more drive systems to the same power line as shown in Figure 2, it will be
necessary to select a circuit-breaking configuration that will ensure that only MCCB2 (not MCCB1)
trips if a short circuit occurs in system 1. If it is not feasible to use this configuration, insert a fuse
between MCCB2 and system 1.
Figure 2. Circuit Breaker Configuration.
16 Q9 Plus Bypass ASD/Bypass Box Installation and Operation Manual