Short-Circuit Protection For Branch Circuits; Control Circuit Protection - Emerson Unidrive M700 Installation Manual

6.2.2 Thermal memory protection
The drives are provided with motor load and speed sensitive overload protection with thermal
memory retention.
The thermal memory protection complies with UL requirements for shutdown, loss of power and
speed sensitivity.
For a full explanation of the thermal protection system refer to the Control User Guide.
In order to comply with UL requirements for thermal memory retention it is necessary to set the
Thermal Protection Mode (Pr 04.016) to zero; and the Low Speed Protection Mode (Pr 04.025) must
be set to 1.
6.2.3 Use with motors with thermal protectors
The drive is provided with a means to accept and act upon a signal from a thermal sensor or switch
imbedded in the motor or from an external protective relay. Refer to the Control User Guide for
further information.
6.2.4 Specific overcurrent protective device
The drive is not required to be connected to a supply source with a specific overcurrent protective
device other than those specified in section 2.4 Ratings on page 13.
6.3

Short-circuit protection for branch circuits

6.3.1 Short-circuit rating
The drive is suitable for use on a circuit capable of delivering not more than 100,000 RMS
symmetrical amperes, 600 Vac maximum, when protected by the overcurrent protective devices as
described in section 2.4 Ratings on page 13.
Unless otherwise indicated in section 2.4 Ratings on page 13, branch fuses may be any UL listed
class CC, J or T rated 600 Vac.
Unless otherwise indicated in section 2.4 Ratings on page 13, circuit breakers may be any UL listed
type with category control number DIVQ or DIVQ7, rated 600 Vac.
6.3.2 Solid state short-circuit protection
The drive is provided with solid state short-circuit protection. Integral solid state protection does not
provide branch circuit protection. Branch circuit protection must be provided in accordance with the
National Electrical Code and any additional local codes.
6.3.3 Common DC bus systems
Frame sizes 3 and 4 are approved for use in modular drive systems using a common DC bus.
For permitted combinations of converter and inverter, along with the required branch circuit
protection, contact Emerson Industrial Automation.
6.4

Control circuit protection

6.4.1 Control circuit wiring
All control circuits are located in limited voltage, limited current isolated secondary circuits. Additional
wiring protection is not required.
Unidrive M/HS Frame 3 and 4 Power Installation Guide
Issue Number: 3
99