Preface
This is the eighth edition of CSA C22.2 No. 77, Motors with inherent overheating protection, part of a series of Standards issued by CSA Group under Part II of the Canadian Electrical Code. It supersedes the previous editions published in 1995, 1988, 1976, 1972, 1970, 1957, and 1942.
The major changes in this edition are as follows:
a) Clause 5.5 on motors with electronic protection has been added;
b) Clause 6.4.5.2 on temperature classes has been clarified;
c) the previous Clause 6.6.6 on motors with thermal cutoffs has been deleted;
d) Clause 6.10 on reliability of electronic protection circuit has been added; and
e) an item addressing electronic protection has been added to Clause 7.1.
For general information on the Standards of the Canadian Electrical Code, Part II, see the Preface of CSA CAN/CSA-C22.2 No. 0, General Requirements - Canadian Electrical Code, Part II.
This Standard has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group.
Scope
1.1
This Standard applies to ac and dc motors with inherent overheating protection designed to be used in accordance with the Canadian Electrical Code, Part I, as follows:
a) motors with a voltage rating not exceeding 600 V and with a protective device connected in the motor circuit;
b) impedance-protected motors with a voltage rating not exceeding 600 V; and
c) motors with a voltage rating not exceeding 5000 V and having a protective device connected in an external control circuit with a voltage rating not exceeding 600 V.
1.2
This Standard applies to motors with protective devices that are responsive to
a) motor temperature alone; or
b) motor temperature and motor current passing through the device but does not apply to motors with protective devices that are responsive to current alone.
1.3
This Standard does not apply to sealed (hermetic) type motor compressors with inherent overheating protection (see CSA C22.2 No. 140.2).
1.4
In this Standard, shall is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; should is used to express a recommendation or that which is advised but not required; and may is used to express an option or that which is permissible within the limits of the standard.
Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material.
Notes to tables and figures are considered part of the table or figure and may be written as requirements.
Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.
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