Supplier Scope of Work for Electrical Process Heaters

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What is included in the Supplier's Scope of Work?

Design, material selection, manufacture, inspection, testing, stamping, and delivery (correct)

Design, testing, and commissioning only

Custom clearance and delivery only

Only material selection and manufacture

What is the Supplier responsible for?

Only the design and manufacture

Only the inspection and testing

The design and delivery

The design, selection of materials and components, manufacturing, and testing (correct)

What is the Supplier's responsibility regarding drawings and documents?

The production of all drawings and documents related to the electrical equipment and materials (correct)

The production of all documents related to the electrical equipment only

The production of all drawings only

The production of all documents only

What is required as per approved Vendor list for electrical equipment and materials?

Make and Country of Origin Signup and view all the answers

What does the Supplier's Scope of Work include if not all works and required material are expressly mentioned in the specification?

Other services complete in every respect even if not all works and all required material are expressly mentioned in this specification Signup and view all the answers

What is the purpose of including a positive 10% performance margin in the calculation of power required for all design cases?

To ensure reliable operation at nominal voltage and frequency Signup and view all the answers

Why should the thyristors employed be sized to ensure that the maximum current flowing through them does not exceed 70% of their continuous rated current?

To prevent overheating and ensure reliable operation Signup and view all the answers

Why is it important to select the maximum watt density on the element surface to ensure no degradation of the process fluid/gas?

To prevent contamination of the process fluid/gas Signup and view all the answers

What is the purpose of verifying the element surface temperature and pressure drop across the heater using an industry recognized process design simulation package?

To validate the heater's performance under different operating conditions Signup and view all the answers

What requirement must be met for heaters to be designed to operate reliably at the maximum voltage?

Thyristors must be sized to limit maximum current flow Signup and view all the answers

What is the design life requirement for the equipment mentioned in the specification?

30 years Signup and view all the answers

How should the power of each heater be controlled according to the specification?

Zero-crossover mode Signup and view all the answers

What should the capacity of the transformer feeding the heater be, in relation to the kVA rating of the heater?

8 to 10 times Signup and view all the answers

What type of control should be used instead of burst firing control for large loads fed from relatively weak supply systems susceptible to electrical disturbances?

Single cycle control Signup and view all the answers

What must the design ensure regarding the mechanical stress and fatigue on the heater elements?

Minimum mechanical stress Signup and view all the answers

What is the purpose of utilizing a combination of fixed elements and a variable element in an electric heater?

To reduce the transformer ratings needed for the electric heater Signup and view all the answers

In what configuration should the load be set for a large electric heater?

Four-wire star or delta Signup and view all the answers

What protection measure should be included for the thyristors in an electric heater?

Over-current protection by ultra-rapid fuses Signup and view all the answers

What type of input signal is required for the control circuit of an electric heater?

4 to 20 mA D.C. signal with a linear relationship from 0 to 100 % power Signup and view all the answers

What is necessary if parallel operation of thyristors is required and approved by the company?

Current balancing shall be applied Signup and view all the answers