Grounding Connection; Additional Installation Instructions; Motors Fed By Variable Frequency Drives; Electrical Characteristics - WEG Ex d Manual De Instalación, Operación Y Mantenimiento

2.5 GROUNDING CONNECTION

Besides the grounding connection provided inside the terminal box, Ex motors are fitted with a second
"grounding connection", attached to the frame.
This must be connected to the general "unit-ground" by means of a conductors section, related to the
line-conductor section as it is described on the table below:
line conductor
S ≤ 16 mm²
16 < S ≤ 35 mm²
S > 35 mm²

2.6 ADDITIONAL INSTALLATION INSTRUCTIONS

Explosion proof motors must be protected against overload by means of a device incorporated into the
motor (i.e, a thermistor inserted into the coil head) or, by independent devices.
On the installation, it is also important to check whether motor cooling is suitable or not.
For this purpose, the minimum distance between motor and any other structure, that can affect cooling,
is given on the table below:
Frame sizes
90 / 100 / 112
132 / 160
180 / 200
225 / 355

3 MoToRs FED bY VaRIablE FREQUEnCY DRIVEs

3.1 ELECTRICAL CHARACTERISTICS

3.1.1. TEMPERATURE CLASS

Motors fed by VFD are suitable to operate at T4 temperature class.

3.1.2 USE OF FILTERS

Motors with voltages up to 575V do not require filters if follow the criteria below:
Rated Insulation
Voltage system
Standard
Vrated < 460V
Insulation
460V < Vrated Reinforced
< 575V Insulation
(*) Informed by the converter manufacturer.
Note: Nameplate showing voltage 380-415V / 660-690V – 50Hz and 440 - 480 – 60Hz, and fed by VFD on
voltage 660-690V – 50Hz or 480V – 60Hz require filters.
Motors fed by VFD with voltage range of 575V up to 690V require filters.
10 | INDUCTION MOTORS FOR HAZARDOUS AREAS
Grounding conductor
0.5 S (mm²)
Minimum Distance from outside structures (mm)
Technical criteria for VFD application
Voltage dV/dt
spikes motor inverter
terminals terminals
(maximum) (maximum)
< 1600V < 5200 V/µs
< 1800V < 6500 V/µs
S (mm²)
16 mm²
30
35
45
85
Rise time(*)
inverter
terminals
(minimum)
> 0,1 µs
MTbP(*) Minimum
Time between Pulse
> 6 µs
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