Firing Board

This guide will take you through all the critical aspects you need to know about firing board.

So, before investing in a new firing board, read this guide.

What is a Firing Board?

You find the industry standard for a firing board to be the Silicon Controlled Rectifier (SCR) firing board.

The SCR firing board is a circuit formation that allows you to deliver gate pulses or initiate a circuit impulse.

You also find the SCR firing board useful in controlling the angle of delay’s current or voltage.

SCR Firing Board

What is meant by Firing?

When you apply a voltage at the gate of an SCR, you initiate firing.

A silicon controlled rectifier is a triple pinned device you refer to as anode, cathode, and the gate.

Silicon controlled rectifier

You typically employ the gate as the control pin when you apply a voltage across the anode and cathode.

There are two types of SCR firing that you will find.

1. Zero Voltage Cross Over/ Fast Cycling

You find this firing method of turning on an SCR to occur at only once instance.

It appears when the sinusoidal voltage’s immediate value is zero.

2. Phase Angle Control Firing

In this case, you find the phase angle differs at points.

There is a delay in activating the pulses at the gate but with a controlled conduction process.

What is the Firing Angle of a Firing Board?

Upon zero crossing, the thyristors in a firing board can be activated.

You find this process occurs at a certain angle, which you refer to as the firing angle.

When you switch on an SCR, a cycle begins that can be defined in degrees.

The degree count from the initial cycle process is what you refer to as a firing angle.

You find two thyristors become forward biased when the voltage source is drained past zero crossing.

The silicon controlled rectifiers are subsequently activated upon achieving a set angle.

How can you Describe the Firing Circuit of a Firing Board?

You will find three firing circuits: R-firing circuit, RC firing circuit, and UJT firing circuit.

Furthermore, you see the following features related to the firing circuit.

• You find such circuits need to generate thyristors activating pulses at defined instances.
• Additionally, the thyristor and the firing circuit should be electrically isolated.

You can use an amplifier for pulses to initiate isolation.

Can you achieve Control of the Firing Angle?

Achieving control of the firing angle is useful in various instances.

For example, you require this control when regulating fans’ motor speed and adjusting a source’s light intensity.

You can control the firing angle by adjusting the intervals when applying pulses to the SCR gate.

You can use a remote input source to vary the time at which a gate voltage is applied.

When you control the firing angle, you determine when the SCR will be activated.

The point at which this happens is when the AC wave formation matches with a supplied DC voltage.

What are the Available Types of Firing Boards?

You find many configurations of the SCR firing board.

These various configurations allow you to extract broad performance capability from your power-based applications.

Some of the types of firing boards you can find are:

i. Single Phase

You use these types of firing boards for single phase-specific applications such as AC motor controllers.

Other applications you find for single-phase boards are field exciters for motors, industrial power supplies, and some bridge rectifiers.

There are different variants of the single-phase firing board that you will find.

These variations are based on the configuration of silicon controlled rectifiers.

You can find a single-phase firing board with two SCRs and some with four SCRs.

You can combine the four SCR single phase motor with specific purpose boards.

For instance, you can employ such a combination in a bridge converter with a four-quadrant configuration.

ii. Three Phase

You find this type of firing board useful in three-phase applications such as power supplies for heavy industry.

Other applications you find for the three-phase firing board are motor controllers, battery charging systems, and power generators.

iii. Six Phase

You find the use of the six-phase firing board is targeted for specific rectifiers and motor controllers.

In a six-phase firing board, you will find twelve silicon controlled rectifiers for pulse command.

Additionally, you can use this firing board type to augment phase balance.

In this case, you employ an auto-balance circuit system that is emphatic on gain.

Furthermore, you can use this firing board type to keep the line operating voltage at a constant value of 900.

What are the Applications of the Firing Board?

The firing board allows you to reliably and cost-effectively apply the phase angle control of SCRs.

You find this especially useful for three-phase applications such as converters relying on DC and AC controllers.

The make-up of a firing board consists of a sextuplet of gate drives isolated from one another.

You also find these gates can be configured individually with commands that allow soft start and stop.

You will find firing boards employed in the following devices and equipment.

• Battery charging systems
• Primary controllers for transformers
• DC motor drives
• Half-wave converters
• Uninterrupted Power Supply systems
• Controllers for wind turbine plants

What are the Features of a Three-phase Firing Board?

You find many different features attached to the three-phase firing board.

You can find these features attached as independent functions of the three-phase firing board.

Some of these features include:

3 Phase firing board

• Six extra gate outputs
• Circuits allowing polarity transition
• Tolerance to high voltage
• Gate pulse transformers with high output values
• More considerable distances to facilitate creepage
• Ability to vary the frequency over five kilohertz for an extended period

Why is Silicon used for the SCR Firing Board?

Silicon is a semiconductor material whose use you find prevalent in the electronics world.

In an SCR firing board, you use silicon since its tendency to leak current is significantly reduced.

The firing board operates to determine the biased nature of the device by establishing the voltage polarity.

The application of voltage is commonly made on the cathode or anode terminals.

Can you Employ LSI in making Firing Boards?

Yes, you can.

LSI is short for Large Scale Integration.

You employ large scale integration when you furnish thousands of transistors on a single microchip.

Using LSI allows you to provide a powerful device on a minimal platform.

The large scale integration is a successor to the medium-scale integration.

You also find it to be a precursor to a very large scale and ultra large scale integration.

The difference in these integration scales is the number of transistors you can integrate onto a component or chip.

What is the Advantage of using LSI on Firing Boards?

Using large scale integration allows you to integrate many transistors on a single microchip.

Consequently, you find several benefits from this technology when you employ it on firing boards.

Using LSI allows you to increase the cost-effectiveness of your firing boards.

You can increase the chip density without positively affecting your cost.

With an increased transistor count on your firing board, its performance is improved.

Subsequently, the reliability of the device is enhanced, extracting maximum benefit.

Is it Possible to Combine Firing Boards with other Circuit Boards?

You can combine the firing board with other specialized boards.

Some of the boards you can connect with include the regulator board, among other purpose-specific boards.

You can also combine a firing board with an auxiliary firing board.

You find that through these combinations, you can achieve a wholesome control bundle for your application.

What are some of the Specifications of the Standard Firing Board?

The firing board finds use in different applications such as plating devices, charging systems for batteries, and power supply equipment.

You will discover other specifications attached to these boards, depending on their application.

Some of the typical firing board specifications you will find include.

• Input signal characteristics of between 5-10 V and 4-20 mA.
• An operating voltage of between 360 -400 Vac at an operating frequency of 50-60 Hz.
• An adjustable output resolution of 1/4000.
• Varied load application, including resistive, transformer, and inductive load.
• A close-tolerance stability accuracy.
• A broad current and voltage adjustment range between 0-100 percent.
• A trigger current equal to or above 600mA.
• A wide operating temperature range between -20 °C and 60 °C.
• A trigger capacity equal to or less than 1000A.
• High dielectric strength and working relative humidity equal to or less than ninety percent.
• Dynamic response time less than or equal to 50 ms.

What is an Auxiliary Firing Board?

An auxiliary firing board is an additional firing board you use to supplement a firing board’s performance.

You can supplement a single firing board with as many as five auxiliaries.

Furthermore, you can use your auxiliary firing board to drive multiple silicon controlled rectifiers.

An auxiliary firing board can manage high input voltages as much as 900 V.

What are some of the Design Aspectsyou Find on a Bi-polar Firing Board?

The bipolar firing board is a three-phase firing board with six silicon controlled rectifiers.

You can configure the board to perform as an AC controller capable of series reversing or a four-quadrant rectifier.

The following design aspects are recognizable on a firing board:

Thyristor control boards

• A triple-double set of output gates.
• A circuit that allows transition of polarity.
• Control inputs for soft start and stop that can be configured independently.
• Command input for a delay angle that is analog-based. You find this input can be configured for a range of current and voltage values.
• Regulator boards for different voltage and current values.
• Auxiliary firing boards allowing parallel and remotely controlled configurations of SCR.

Where do you use the Bi-polar Firing Board?

You find the bi-polar firing board to be a cost-effective and efficient three-phase circuit configuration.

It allows you to control the silicon-controlled rectifiers’ phase angle for direct current converters and AC controllers.

You will find the bi-polar firing board useful in the following areas:

• Half-wave converters.
• Rectifiers used for plating.
• Primary controllers for transformers.
• Controllers for wind turbines.
• Motor drives that are based on direct current.
• Battery charging systems.
• Uninterrupted power supply systems.

What are the Outstanding Operational Features of Bi-polar Firing Board?

The bi-polar firing board has several features that you find outstanding and useful for its efficient operation. They include:

• An analog command signal for angle delay. You can select various current and voltage value ranges for your signal that is DC controlled.
• You can soft-start the firing board where the angle of command readjusts the signal value to the set point.

Alternatively, a soft-stop causes the set value’s adjustment to the maximum threshold before preventing the rectifiers from firing.

• The device powers on upon resetting. You find the bi-polar firing board is wired to thwart unintended gate activation when the device is powered.
• When there is a phase discrepancy along the AC path, a specific circuit counters the loss preventing SCR firing. You find a soft-start occurs when the failing is addressed.
• The SCR gate system is not altered by the phase sequence of the voltage derived from the mains.
• There is a transistor, switch, and relay system that you employ to facilitate instantaneous enabling or firing inhibition. You find this to occur in line with the high signal instruction with a corresponding angle of delay.
• You can select from different power sources such as an external voltage source of 24-30 V. Additionally; you can connect the board to a transformer with an external supply voltage of between 120-480V.
• There’s a unique compensation circuit with this firing board. You find it useful in controlling the variance of the angle of delay with the frequency.
• You find a gate drive with picket fence qualities that can operate at high current values. You will find this gate drive to have a very high burst frequency. The frequency value is about 400 times that of the voltage from the mains.

Can you use SCR Firing Board as a Switch?

Yes, you can.

The SCR firing board can be forward or reverse biased by the voltage applied on the positive or negative terminal.

When this happens, you find the conduction of the SCR is determined by the voltage at the gate.

Consider applying a positive voltage on the gate, causing the SCR to be in forward bias.

Conduction is initiated, and you can turn it off by reducing the device current to below the holding current value.

What is the High Voltage Firing Board?

The high voltage firing board is one you find with a tolerance for high voltage values.

Additionally, you find this board type to possess pulse transformers with high-output gates.

Another characteristic you note is the enhanced creepage distance that offers improved isolation to the AC path’s voltages.

This quality augments the trigger current for the gate, especially for devices with large surface areas.

Is Phase Sequence Distortion an Issue on the High Voltage Firing Board?

Phase sequence distortion occurs along the AC line, where you find altered values resulting in unsanctioned SCFR firing.

You find the high voltage firing board unaffected by distortion of the phase sequence and the mains voltage.

Furthermore, with the high voltage firing board, you find the gate isolation to be high.

Additionally, the firing board prevents phase loss while initiating an instant soft start and stop commands.

Can you use High Voltage Firing Board as a Primary Controller for a Transformer?

Yes, you can.

A transformer is an electrical device fashioned to carry out an electrical current conversion of AC type to different voltage values.

You find transformers useful in the transfer of electrical energy between circuits.

You find these properties allow you to use the high voltage firing board as a transformer’s primary controller.

• The firing board has an isolated gate drive, which you find a picket fence with high current support.
• You can instantly enable the high voltage firing board while inhibiting phase loss.
• The high voltage firing board allows you flexibility regarding the control of power options.
• You find this firing board type to be insensitive to enhanced frequency values and the distortion of the mains voltage.

How does a Variable Frequency Firing Board Work?

A variable frequency board allows you to employ a standard firing board where the AC supply frequency is variable.

You can find variable frequency firing boards operating at frequencies between 30-140 Hz.

You find a variable firing board working to be based around a detached converter for DC to DC.

There is a frequency-specific compensation mechanism that you find responsive to the circuit path’s insensitivity to frequency variations.

The direct current only converter is responsible for the heightened flexibility in controlling the power.

You can customize your frequency range for the variable frequency firing board.

Pulse gate firing board

What are the Quality Standards for Firing Boards?

Standards are set by oversight bodies that develop design and system guidelines ensuring quality firing boards.

You find standards are useful in preventing the distribution of inefficient and harmful products.

Some of the standards used for firing boards are:

· IEC61000-4

The standard provides for a test and measurement protocol for the electromagnetic compatibility of firing boards.

· IEC60947-4-2

You find this standard is specific to control and switch gears with low voltage values.

It includes starters and AC controlled motors.

· IEC65

Where firing boards are employed in household equipment, you find this standard useful in establishing their safety.

Of particular concern is equipment utilizing grid power.

· GB3797-89

You find the above standard includes guidelines for electronically controlled equipment and devices such as the firing board.

As a professional designer and manufacturer of PCBs, Venture Electronics adheres to strict quality standards – from choice of material, fabrication to testing.

Besides, we offer the best prices in the industry.

Contact us today for all your firing board needs.