Crusher / Feeder Speed Control VSDs Setup
Crushers (especially Hammer / Impact / Jaw Crushers) are mainly used for primary crushing of large pieces of materials. These are typically harsh working environments with heavy loads. These applications therefore have a high risk of overload (causing the system to stop running) due to uneven feeding or hard/large materials entering the crusher and getting stuck in the crushing chamber or between the rollers.
These overload conditions typically result in a very high spike in current drawn by the motor (various risks associated with that), which, from a VSD perspective, typically cause the VSD to trip (Err10 Overload or Err02/03/04 Overcurrent fault protection). VSDs typically has limitations to its overload capacity (typically rated current 1.5 times for 60s, 1.8 times for 3s, or instantaneous protection at 2 times rated current), please see FAQ entry HERE for a more detailed explanation on this.
* Note that for Hammer / Impact / Jaw Crushers (due to above implication), it is generally advised to rather use a Soft Starter (instead of VSD), but for scenarios where a VSD is required (due to additional functionality and features when compared to Soft Starters), the following setup and VSD selection is suggested:
For both the main Crusher Motor and the Feeder (Feeding Conveyor Belt) Motor, select VSDs (kW) of two sizes larger than the Motors (kW). For the Vibrating Screen Motor, select a VSD (kW) size larger than the Motor (kW). In addition to this (from setup perspective), the feeding speed of the conveyor belt should be controlled by the current of the main crusher motor (to reduce the feeder speed when the current of the crusher motor is large), and the feeder motor should only start once the crusher motor is running.
For the Feeder VSD start/stop control, the Crusher VSD relay (TA2/TC2 or TA/TC) is used to ensure that when the Crusher VSD reaches the FDT1 detection frequency, the relay output triggers the start-up of the Feeder VSD (and thus only starts the feeding process once the crusher is running at the desired speed). When the frequency is lower than the FDT1 detection frequency, the Crusher VSD relay (TA2/TC2 or TA/TC) is disconnected and the Feeder VSD will stop the Feeder Motor.
For speed control the AO1/GND analog output of the Crusher VSD (0-10V signal) is used as input to the AI1/GND analog input of the Feeder VSD. This is thus used as a closed-loop PID control setup to avoid overcurrent protection shutdown of the Crusher VSD (by controlling the feeding speed based on the Amps drawn by the Crusher Motor).
In addition to this, the AI1/GND analog input of the Feeder VSD is set up with a limit to ensure that when the Crusher VSD Amps reaches a too high value, the Feeder VSD is stopped immediately (use b5-06 to set the limit, which will initiate a fault when reached – fault needs to be reset manually).
Wiring Diagram:
Parameter Settings:
For both VSDs, ensure to set the Motor Parameters (d0-00~d0-04) according to the Motor Nameplate details and then perform the Auto Tuning (d0-30).
Crusher VSD Parameters:
- Set b4-03 = 17 (Relay 2 Function set as FDT1 Output which will be used as trigger to open/close the relay)
- Set b4-22 = 45 (FDT1 set at 45Hz which will be used as the trigger frequency to open/close the above relay)
- Set b4-23 = 0 (Frequency Detection Hysteresis set to use a 0% offset)
- Set b6-01 = 2 (AO2 Output Function set to use the Motor Output Current – corresponds to 0~Double the Motor Rated Current)
*In addition to the above one would typically adjust the Acceleration (set b0-21 = 60s) and Deceleration (set b0-22 = 200s) times as needed and also use an External Start/Stop Switch (see FAQ entry HERE) and an Emergency Stop (see FAQ entry HERE).
Feeder VSD Parameters:
- Set b0-02 = 1 (Command Source Selection set as Terminal Control to allow Start/Stop via the Crusher VSD relay)
- Set b0-03 = 8 (Main Frequency Source X Selection set as PID to allow speed control based on Crusher Motor Amps)
- Set b1-07 = 1 (Stop Mode set as Free Stop)
- Set b5-05 = 0 (AI1 Input Voltage Lower Limit of Protection set to be irrelevant)
- Set b5-06 = 8 (AI1 Input Voltage Upper Limit of Protection set as additional protection against overcurrent – 8V corresponds to 1.6 times the Crusher Motor Current reached, which will initiate Err27 Fault Protection – used by b7-00 and b7-00 that follows)
- Set b7-00 = 40 (VDI1 Function Selection set as User Defined Fault1 to be used which will be triggered based on b7-11 that follows)
- Set b7-11 = 34 (VDO1 Function Selection set for AI1 Input Exceeded Limitation which will trigger fault b5-06 based on the value limit set using b7-00)
- Set C0-00 = 0 (PID Setting Source set as C0-01)
- Set C0-01 = 40% (PID Digital Setting set as the desired speed of the Feeder Motor – adjust according to specific scenario to ensure Crusher Motor Amps is as desired when operating normally – typically use Target Crusher Motor Current / (2 * Crusher Motor Rated Current) – this is because AO2 is rated up to double the motor rated current)
- Set C0-03 = 0 (PID Feedback Source set to use AI1)
- Set C0-07 = 0.1 (Integral Time TI1 set to have a response time of 0.1s)
- Set C3-09 = 0 (Set Sleep Selection as Active/Available)
*In addition to the above one would typically adjust the Acceleration (set b0-21 = 10s) and Deceleration (set b0-22 = 6s) times as needed and also use an Emergency Stop (see FAQ entry HERE).
