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SEMI S22-1103a © SEMI 2003, 2005 30 18.4.4 The incomi ng circuit or fee der to power con v ersion eq uipm ent, included as part of an adjustab le speed drive system, shoul d be based on the rated input to t he power conv…
SEMI S22-1103a © SEMI 2003, 2005 29
EXCEPTION: Equipment that meets the wire bending space requirements of NFPA 70 will also meet these criteria.
17.10 Conductors should be designed so that their current carrying capacity is not impaired by mechanical,
chemical, or any other influences.
18 Electric Motors 186 Watts (1/4 Horsepower) and Larger
18.1 General The considerations provided in this section apply to electric motors and their electrical enclosures.
This includes the considerations for overcurrent protection. This section applies to AC and DC motors, 600 V or
less, 186 Watts (1/4 HP) and larger.
18.1.1 Remotely installed (for example, in a chase or sub-floor) motors should have a means of disconnecting all
unearthed conductors within sight of and not more than 3 meters (10 feet) travel distance of the motor.
18.1.2 Motors should be protected from ingress of liquids that may lead to increased risk of electric shock or fire.
The motor terminations to supply conductors should be in the motor housing or a separate enclosure provided for
this purpose.
NOTE 51: Assessment of risk generally involves consideration of single-fault tolerance (see ¶7.4 and ¶10.1).
18.1.3 The motor should be marked with the manufacturer’s name and part number. The motor should be marked
with directional arrows, if lack of this information could result in a safety concern.
NOTE 52: Phase identification is one method of identifying correct connection for motor direction.
18.1.4 Motors should be marked with their voltage, current and frequency rating.
EXCEPTION: This information can be provided in support documentation if it can be traced to the manufacturer’s
name and part number on the motor.
18.1.5 Under-voltage protection should be provided for all motors that could initiate hazardous equipment motion
when power is returned after an under-voltage condition.
18.2 Motor Mounting And Compartments
18.2.1 Each motor and its associated couplings, belts and pulleys, or chains, should be so mounted that they are
adequately guarded and may be serviced without putting personnel at risk of injury.
18.2.2 Construction should ensure proper cooling and that any rise in temperature remains within the limits of the
motors’ insulation class.
18.2.3 Applicable points on the motor should be accessible for lubrication, maintenance, and replacement.
18.2.4 Sufficient air circulation to maintain temperature within the motor rating should be provided.
18.3 Mechanical Brakes Where the operation of a mechanical brake increases the potential for entrapment or
other hazards, a method of brake release should be provided.
18.4 Protection of Motors
18.4.1 Overcurrent protection should be provided for motors. This protection should be sufficient to protect against
overcurrent conditions due to faults in the insulation, locked rotor, or overload conditions. The overcurrent
protection should open all unearthed conductors.
18.4.2 Where an overcurrent protection device may permit motor starting and still provide overload protection it
may be used for both purposes. However, a single device may not be suitable for both overcurrent and overload. In
such cases two separate devices should be used; one suitable device for short circuit and ground-fault protection and
the other for overload protection.
18.4.3 Overload protection should be in the form of one of the following:
a) overload relay,
b) thermal protection internal or external to the motor, or
c) impedance protection.
SEMI S22-1103a © SEMI 2003, 2005 30
18.4.4 The incoming circuit or feeder to power conversion equipment, included as part of an adjustable speed drive
system, should be based on the rated input to the power conversion equipment. Unless the power conversion
equipment is certified by an accredited testing laboratory to indicate that overload protection is included and suitable
for the motor, additional overload protection should be provided.
18.4.5 Over-speed protection should be provided in cases where over-speed may cause a hazardous condition.
19 Accessories and Lighting
19.1 Lighting Circuits
19.1.1 One conductor of all equipment lighting and maintenance lighting circuits should be bonded to the
equipment protective earthing system in accordance with ¶19.1.2 or 1¶9.1.3. See ¶17.6.3 for conductor
identification.
19.1.2 Where the lighting circuit is supplied by a separate transformer, the earthing should occur at the transformer.
19.1.3 When the protective conductor is connected to a screw-shell lamp holder, it should be connected to the screw
shell.
19.1.4 The conductors connected to stationary lights used as an integral part of the equipment should be suitable for
their application.
19.1.5 Equipment work lights should not contain switches or receptacles such that exposure to liquids or other
substances may increase the risk of electric shock or fire.
NOTE 53: Switches or receptacles should be located where liquids or other substances will not increase the risk of electric
shock.
19.2 Attachment Plugs and Receptacles
19.2.1 Attachment plugs and receptacles should be rated and labeled for the applied voltage and current.
19.2.2 Where used in circuits of 300 Volts or more, attachment plugs and receptacles should be rated for the
application (load break or no-load break), and constructed to contain any arc generated when a connection is made
or broken.
19.2.3 Attachment plugs and receptacles should be designed or installed to prevent the ingress of substances that
may increase the risk of electric shock or fire.
19.2.4 Receptacles internal to the electrical enclosure should be permitted only for maintenance equipment or AC
power distribution within the enclosure to assemblies designed and approved for cord-and-plug connection. See
¶17.3 for more details regarding receptacles.
20 Markings
20.1 General Hazard alert signs, nameplates, markings, and identification plates should have sufficient
durability to withstand the anticipated physical environment where the equipment will be installed.
20.2 Hazard Alert Signs Enclosures should be labeled to inform the end user of the hazards that they enclose.
These labels should comply with SEMI S1.
EXCEPTION: This labeling is not necessary where the enclosures are interlocked with non-defeatable interlocks to
disconnect the hazards in question.
20.3 Functional Identification Control devices, visual indicators, and displays should be clearly and durably
marked with their functions either on, or adjacent to, the items. Refer to ¶14.2.2, Markings.
20.4 Equipment Nameplate A permanent nameplate should be attached to the main electrical enclosure or
equipment where it is plainly visible after installation. This nameplate should include the following information:
a) the manufacturer’s name and address,
b) the equipment name, model, and serial number,
c) supply voltage,
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d) number of phases,
e) number of wires,
f) frequency,
g) full-load current,
h) ampere rating of the largest motor or load,
i) short-circuit interrupting rating of the equipment main overcurrent protective device,
j) ampere rating of the overcurrent protective device where furnished as part of the equipment, and
k) the electrical diagram number(s) or the number of the index to the electrical diagrams (bill of material).
20.5 Where more than one incoming supply circuit is to be provided, the nameplate should state the above
information for each supply circuit.
EXCEPTION: Where the only load is a single motor or motor controller, the motor nameplate is permitted to serve
as the electrical equipment nameplate when it is plainly visible.
20.6 Full Load Current — The full-load current shown on the nameplate should not be less than the full-load
currents for all motors and other equipment that may be in operation at the same time under normal conditions of
use. Where unusual loads or duty cycles require oversized conductors, the necessary capacity should be included in
the full-load current specified on the nameplate.
20.7 Overcurrent Marking — Where overcurrent protection is provided in accordance with ¶9.1.5, the equipment
should be marked “overcurrent protection provided at machine supply terminals.” A separate nameplate may be
used for this purpose.
20.8 Reference Designations All enclosures, assemblies, control devices, and components should be plainly
identified with the same reference designation as shown in the technical documentation or identified through
equivalent means.
21 Technical Documentation
21.1 Installation Diagram The installation instructions should give all the information necessary for complete
installation and safe start up of the system. This should include:
a) a comprehensive description of the equipment, installation and mounting, and the connection to the electrical
supply or supplies, and
b) an explanation of the equipment’s installation instructions including facilities supply conductors.
21.2 Block (system) Diagrams and Functional Diagrams When it is necessary to facilitate the understanding of
the principles of operation, a block (system) diagram should be provided. A block (system) diagram symbolically
represents the electrical equipment together with its functional interrelationships without necessarily showing all of
the interconnections.
21.3 Circuit Diagrams Circuit diagrams or schematics for power distribution, EMO and interlock circuits should
be provided. Where a block (system) diagram does not sufficiently detail the elements of the electrical equipment
for safe installation and servicing, circuit schematics should be furnished.
21.4 Operating Instructions The end user documentation should include operating instructions detailing proper
procedures for operation of the equipment. Particular attention should be given to the safety measures provided and
to the improper methods of operation that are anticipated.
21.5 Maintenance Instructions The technical documentation should contain maintenance instructions detailing
procedures for servicing and maintaining the equipment. Attention should be given to how these procedures may be
performed safely. A preventative maintenance schedule should be provided with the equipment.
21.6 Functional Description of Interlocks — A functional description of interlocks should be provided which
provides sufficient detail to explain their operation.