How to use VFD on Fiberglass Drawing machine?

The operating principle of a fiberglass drawing machine is quite straightforward. It involves melting glass marbles, which serve as the raw material, and then rapidly pulling the molten glass into strands of fiber. These strands are subsequently wound into rolls of fiber of a predetermined size following a specific pattern. The drawing section primarily comprises components such as a crucible, tank furnace, drawing machine, and a temperature control system.

Process Flow

The drawing machine’s process flow is segmented into several systems: a. Winding system, b. Spray system, c. Oiling system, d. Bundling system, e. Leak plate system

• Winding System: Central to the winding system is the drawing machine, with VFD (Variable Frequency Drive) controlling the winding process. Its principal function is to stretch the glass liquid exiting from the leak plate nozzle into glass fibers of a specific fineness and systematically wind these into raw silk tubes. These tubes are designed to meet specific requirements for the next stage of the production process.

JHI600 Series Drawing Machine Variable Frequency Control

Control over the glass drawing machine is executed via multifunction terminals, relay output terminals, and external circuits.

1. The VFD initiates acceleration only upon detecting a set frequency and operation signal.
2. By setting a lag frequency, the machine is programmed to automatically stop once a tube of silk is drawn and the lag frequency is reached, under normal conditions.
3. The VFD decelerates over a time frame of 0 to 6550 seconds, ensuring consistent pulling force despite variations in coil diameter, which achieves the production requirement of uniform fiber thickness.
4. During coil changes, an external circuit manipulation instantly disconnects the VFD’s operation signal, prompting a recalculation of the lag frequency.

The control system composed mainly of the JHI600 series VFD

1.Main circuit wiring

Note:

When the VFD is connected to one or more motors, the motor and the VFD must be directly connected. A contactor or air switch cannot be interposed between them, as this would lead to excessive current impact and could damage the VFD.

2.Control circuit wiring

Note:

1. Typically, a drawing machine’s winding motor is 0.75KW, for which a 2.2KW G-type VFD is selected (applied in an amplified setting).
2. A braking resistor can be incorporated should an OU overvoltage condition arise during a free stop.

Precautions When Utilizing VFD in Drawing Machines

1. If the site setup involves wall divisions as illustrated in figures 1-3, waterproofing concerns can be disregarded. Otherwise, precautions against water ingress are crucial to avoid potential VFD damage.
2. The presence of glass fiber fragments at the site necessitates vigilant maintenance of fan ventilation to prevent clogging of the vent by glass fibers, which could lead to VFD overheating (indicated by OH1) or component degradation from excessive heat, consequently reducing the VFD’s lifespan.
3. Parameter adjustments should not be made by individuals without technical expertise.

Benefits Post-Modification

Employing an inverter in the glass drawing machine allows for independent operation at the maximum frequency with a deceleration time ranging from 0 to 6550 seconds. It also facilitates automatic operation of the drawing machine through system settings. Given that around 10Hz marks the maximum reduction range of the VFD’s operating frequency, the deceleration time can be adjusted between 0 to 6550 seconds by setting the decrement rate parameter. This enables the VFD to meet various production process control needs for drawing products. Consequently, the drawing machine’s operation remains stable while simplifying operational procedures, effectively minimizing waste due to operational delays. Furthermore, the VFD’s integrated motor protection features not only reduce the equipment’s failure rate but also decrease maintenance costs, thereby enhancing the efficiency of production equipment and serving as an effective means to boost the economic benefits for enterprises.