Electrical Systems & Mechanical Components Flashcards
7 cards from real CST practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Electrical Systems & Mechanical Components flashcards as text
NTEP Certificate of Conformance (CoC) requirements specify that a Class III commercial scale must have a minimum verification scale interval (e) of:
Answer: 0.01 lb
NTEP specifies that Class III scales must have a minimum verification interval of at least 0.01 lb (or equivalent metric) for commercial trade applications.
A technician notices that a digital indicator's display flickers between two adjacent counts under a stable load. The most appropriate corrective action is to:
Answer: Adjust the digital filter or averaging setting in the indicator
Display flickering between two counts under a stable load is typically caused by noise at the A/D level and is corrected by increasing digital filtering or averaging.
What is the purpose of the 'creep compensation' specification on a load cell data sheet?
Answer: To describe output drift over time under constant load
Creep is the slow change in load cell output over time while a constant load is maintained, and the specification defines the maximum allowable change.
Which type of connector is most commonly used for environmentally sealed load cell field connections in harsh industrial environments?
Answer: Mil-Spec circular connector with IP67 rating
Mil-Spec circular connectors with IP67 or higher ratings provide the moisture and dust sealing required for load cells in washdown and outdoor environments.
When calibrating a scale using a substitution weight method, the technician uses calibrated test weights to:
Answer: Verify the scale's reading against known reference masses
Substitution calibration compares the scale's reading against NIST-traceable test weights to verify accuracy and adjust span if needed.
A cable with a shield connected at both ends in a scale system is most susceptible to:
Answer: Ground loop interference due to potential differences between endpoints
Connecting a shield at both ends creates a ground loop if the two endpoints are at different potentials, allowing interference current to flow through the shield.
What is the function of the 'corner correction' (corner trimming) procedure performed during scale installation?
Answer: To balance load cell outputs so all platform positions give equal readings
Corner correction trims individual load cell contributions (via resistors in the junction box or indicator software) to ensure equal readings regardless of where the load is placed.