RNMV-G (three-in-one) medium and high voltage solid state soft starter is composed of four parts: RNMZ handcart type series medium and high voltage solid state soft starter, circuit breaker, integrated protector, and bypass contactor.

Working principal

The control core of RNMV series product is microprocessor (CPU), which starts and protects the motor.

CPU controls the SCR to conduct phase angle trigger control, lowering the voltage on motor, then controls the voltage on motor and increases the motor torque of the smooth current until motor runs in full speed. The above way of starting can lower the inrush current of motor, reducing the impact on power grid and motor itself. Meanwhile, it also reduces the mechanical impacts on motor loading device, prolonging device service life and reducing motor breakdown.

Type G (Handcart) MV/ HV Soft Starter’s Primary System Diagram：

Note: Cabinets shall be combined for use.

Technical Characteristics

○ A qualified controlling system passed through the strict test of Electro Magnetic Compatibility, processes with a high anti-electromagnetic interference performance; has fully independent intellectual properties in soft starter controlling technology; is capable of providing free service for users in upgrading software control systems to ensure an advance place of its products and technology.

○ It adopts the dynamic fuzzy control concept to automatically adjust motor’s starting time and torque according to the size of load torques, realizing smooth acceleration in motor. When motor speed reaches the rated working level, the bypass contactor shall automatically pull in, which solves an unmatched problem between man-made starting curve and load torque curve. Also known as a unique feature in MV/HV solid soft starter cabinet of our company compared to domestic peers.

Strong load adaptability, with 3 starting control modes:

○ Voltage ramp start: The factory setting is a voltage ramp with current limiting function, which can meet most applications. The initial torque is set to the value when the motor can just drive the load, and then the voltage gradually rises smoothly. Within the limited ramp time and motor starting current range, the motor can smoothly rise to full speed operation;

○ Current limit starting: When starting, the current quickly increases to the limit value until the motor runs at full speed;

○ Pulse kick start: Mainly used for heavy loads.

○ Free parking or soft parking is optional: it can be applied to different parking lots, such as eliminating the water hammer effect of the water pump, to meet special needs;

○ Text display function: LCD liquid crystal screen displays various working conditions and various languages are available, and there are text display instructions under programming and fault conditions, and the operation is intuitive and convenient;

○ System communication function: built-in communication port. RS-485 and remote terminal equipment multi-point communication (communication protocol Modbus and Porfibus optional) can directly communicate with the upper PC through this function to achieve remote control and remote signaling functions.

Applications

It is widely used in the squirrel-cage AC asynchronous and synchronous motors of power system, machinery manufacturing, cement production, metallurgy, mining, oil extraction, chemical
industry, water treatment and others. It is used for MV/ HV motor start, control, protect and soft-stop as three phase voltage of 3KV~10KV.

Technical index：

● Load type: Three-phased squirrel-cage AC asynchronous and synchronous motors

● AC voltage: 3kV, 3.3kV, 6kV, 6.6kV, 10kV AC-15%~+10%

● Insulation voltage: Line voltage: 3000V, 6000V, 10000V; Insulation voltage: 18000V, 25000V, 42000V

● Overload capacity: Continuity: 125% of controller nominal value; Overload: 500% 60 Seconds

● Frequency: 50Hz/60Hz±2Hz Auto choice

● Main circuit Components: (12 SCRS, 18SCRS OR 30SCRS Depends on the models)

● SCR Peak reverse voltage: 13000V~32500V(Decided by model)

● Phase sequence: RNMV is allowed to operate under any phase and sequence

● Instantaneous overvoltage protection: dv/dt Absorb network

● Cooling: Natural cooling

● Bypass: It has the bypass vacuum contactor which can directly start capacity. When the rated current is over 450A, fixed vacuum circuit breaker shall be adopted.

● Ambient Conditions: Cabinet temperature: 0℃~50℃(32℃-122℃); Base temperature 0℃-50℃, (-20℃-50℃ an option of a heater); Altitude of no more than 2000 meters, a relative humidity of 5%-95%; reduced capacity shall be adopted for the altitude of over 2000 meters.

● Control way: The user provides 2 or 3 line of 220 VAC or 220VDC, 1000VA.

● Auxiliary relay: C-type dry relay, 5-10A 250V, one programmable interlock relay, one bypass relay, one fault output; Relay

Motor Protection

● Current: Two-phase timing, inverse-time limit over-current protection (limiting time quick-acting relay, limited to Type G, over-current); Two-phase negative sequence timing, inverse-time over-current protection (negative sequence limiting time quick-acting relay, limited to Type G, negative sequence over-current)

● Overload: Motor shaft lock protection & Overload alarm

● Temperature: Protection from the temperature relay (Over temperature & temperature rise)

Protection for soft-start

● Temperature: Protection for the SCR components; it shall trip when the temperature is higher than 85℃.

● Protection for over-time starting: It shall trip when the starting time is more than 120 seconds.

● Input Phase Loss: Any one loss in the three-phase power shall cause motor failure and alarm.

● Starting times in an hour: No than 6 times of starting in an hour; minimum starting interval: 5 minutes

Model Explanation：

Type G MV/ HV Soft Starter Cabinet Body Schematic Diagram：

Type G MV/ HV Soft Starter Installation Way:

Model Selection Table for RNMV-G MV/HV Solid Soft Starter：

Remark:
1. Bearing capacity of the soft starter: when a motor starts, the maximum starting time permitted is 15 seconds if the starting current is 5 times of the rated current one, 40 seconds for 4 times, and 70 seconds for 3 times; otherwise, please choose the product with higher power.
2. When the motor power is higher than the motor power, we shall choose the product with higher power.
3. If the motor power is within 2000kw, a differential protection box shall be added;
4. The rated current of the soft starter shall be stated according to the rated current of user’s motor.
5. The plan of Three into One shall not be used into type G products of over 370A in rated current.