Toshiba VF010H05 用户手册

· 

Coast-To-Stop Mode: Power is immediately removed from the motor and the 

soft starter returns to the Ready Mode.

Additional protection features activated when the stop command is given include:

·  Coast-Down / Back Spin Timer 

·  Starts-per-Hour 

·  Time Between Starts

·  External Input Faults

The JKSSS+ Series plays an important role in the protection of your motor in that it 

monitors the motor for excessive thermal conditions due to starting, running or even 

ambient conditions. The soft starter has a Dynamic Thermal Register system in the 

CPU that provides a mathematical representation of the thermal state of the motor. 

This thermal state information is kept in memory and is monitored for excesses in 

both value and rate of change. Input is derived from current  imbalances and RTD 

measurements making it dynamic to all processes involving the motor. The starter 

monitors these conditions separately during Start and Run modes to provide proper 

thermal overload protection at all times. 

Start Mode overload protection is selectable using one of three methods:

· 

Basic Protection: I

2

t data is accumulated and plotted based on an Overload 

Curve selected in programming. This is programmed per NEMA Class 5-30 

standard curves and is based on the Locked Rotor Current (from the motor 

nameplate) as programmed into the soft starter.

· 

Measured Start Capacity: The user enters a measured amount of thermal 

capacity from a pre-selected successful start as a setpoint to the Thermal Reg-

ister for the soft starter to follow.

· 

Learned Curve Protection: The user sets the soft starter to the “LEARN” 

mode and starts the motor under normal starting conditions. The CPU then 

samples and records 100 data points during the start curve, analyzes them and 

creates a graphical representation in memory. The soft starter is then switched 

to Curve Follow protection mode and monitors motor performance against this 

curve. This feature is especially useful in initial commissioning tests to record a 

base line performance sample (in this case, it is not necessarily used for motor 

protection).  

     

Run Mode overload protection is initiated when the starter determines that the 

motor is At-Speed. Overload Protection is initiated when the motor RMS current 

rises above a “pick-up point” (as determined by the motor nameplate FLA and 

service factor). Run mode protection is provided by the CPU monitoring the Dy-

namic Thermal Register. Data for the Dynamic Thermal Register is accumulated 

from I

2

t calculations and cooling rates. A trip occurs when the register reaches 

100% as determined by the selected Overload Protection Curve (NEMA Class 

5-30 standard curves) and is based on the programmed Locked Rotor Current 

indicated on the motor nameplate. The Dynamic Thermal Register is altered, or 

“biased”, by the following conditions:

· 

Current Imbalance: Will bias the register higher to add protection from ad-

ditional motor heating during a current imbalance condition.

· 

Normal Cooling: Provided when the motor current drops below the pick-up 

point or the motor is off line. The cooling rate is lower for

 motors that are off-line 

(such as after a trip) since cooling fans are also inoperative