Cane Unloader Crane
Conversion Star/Delta Starter to GA700 VFD
Cane Unloaders are commonly used in sugar mills designed to unload cane from open trolleys specially designed these cane unloaders have a unique feature which allows them to grab material up to 10 feet long in a single lift.When lifting heavy load or material, it is sometimes beneficial to use two cranes in tandem rather than a single higher-capacity crane. During lower load requirement same crane can be used with single motor as well.
Comparison with A Conventional system and VFD
Conventional S/D starter in crane |
YASKAWA VFD-GA700 in crane |
|---|---|
High chances of contactor burn or damage due to frequent start stop operation. |
With multiple number of start and stops-components are not damaged. Saves maintenance time and cost of contactors used earlier. |
No smooth start/stop operation |
Controlled smooth start/stop – gives longer motor life. |
High Inrush current |
Starts with intelligent multilevel frequency – minimal inrush current. |
No input/ output protection or motor protection |
With protection features like Input phase loss, output phase loss, motor overload, motor over heat, motor current limit, Momentary Power Loss ride through, etc. – Extends the system life. |
Observed Motor temperature – continuous 65 deg C |
Motor temperature is less than 400C during operation. Leads to longer motor life and lower maintenance time. |
No intelligent operation of motor brake system |
With controlled operation of brake andoutput , smooth brake release/close – leads to low maintenance of brake |
Due to continuous operation and over temperature/heat, motor burns with in short period. |
With GA700 drive, control temperature remains at minimum allowable level of 40 deg and protects the motor from burning or getting damaged. |
No energy saving |
With intelligent operation sequence energy savings can be maximised based on load conditions. |
Challenges:
- To achieve high precision in load sharing.
- Healthyinterlock verification.
- Smoothening of Torque and Current output in both motors.
- Synchronized operation of motors in tandem control
Solution Offered:
- Yaskawa and Radiant System supplied two no. of GA700 – 103Amps, Cane unloader
- Each drive was connected to an individual motor.
- Drive Model : GA700, CIPR-GA70D4103ABMA,
- Motor Data: 960RPM, 72A,3 phase 415 VAC ,50 Hz ,45KW, S1 duty
Key Benefits & Results:
- Motor temperature reduced by 25 °Cwhen compared with previous system.
- Failure of motor has significantly reduced with VFD.
- Elimination of contactors replacement and maintenance.
- Usage brake logic to control brake to achieve zero load slip.
- Power savings is possible when compared to conventional system.
- Reduced vibrations during hoisting and lowering
- Low starting current when compared with conventional system
- Smooth and controlled operation.
- Easy & reliable operation control
- Inbuilt motor protection functions which eliminates the need for additional protection relays.
- Better speed & torque response.
