Safety and Operating Instructions

AN2316 - Application Note

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3.2

Environmental Considerations

The STEVAL-IHM006V1 AC chopper demo board must only be used in a power laboratory.

The high voltage used in any AC drive system presents a serious shock hazard. A complete

laboratory setup consists of:

●

an isolated AC power supply,

●

the STEVAL-IHM006V1 demo board,

●

an AC Induction motor, and

●

an isolated (laboratory) power supply for +15V (as needed).

The Kit is not electrically isolated from the AC input. The microprocessor is grounded

without insulation with respect to the mains so that it and the associated circuitry are hot.

They MUST therefore be isolated from user controls and serial interfaces.

Note:

Any measurement equipment must be isolated from the main power supply before powering

up the motor drive. To use an oscilloscope with the Kit, it is safer to isolate the AC supply

AND the oscilloscope. This prevents a shock occurring as a result of touching any SINGLE

point in the circuit, but does NOT prevent shocks when touching TWO or MORE points in

the circuit.

An isolated AC power supply can be constructed using an isolation transformer and a

variable transformer. A schematic of this AC power supply may be found in the Application

Note, “AN438, TRIAC + Microcontroller: Safety Precautions for Development Tools”.

(Although this Application Note was written for TRIACs, the isolation constraints still apply

for fast-switching semiconductor devices such as IGBTs).

Note:

Isolating the application rather than the oscilloscope is highly recommended in any case.

3.3

Mandatory Checks Before Operation

The following verifications must be performed before operating the demo board:

●

The motor load is connected and earth-grounded,

●

there is no metal part on, below, or around the PC boards, and there are no unintended

earth/ground loops caused by peripheral (e.g. test) equipment (e.g. PC or

oscilloscope), and

●

the motor and mechanical load are safely housed so that rotating parts cannot be

inadvertently accessed and cause injury (e.g., loose clothing, long hair).

Warning:

The high voltage levels used to operate the motor drive could

present a serious electrical shock hazard. This demo board

must be used only in a power laboratory only by engineers

and technicians who are experienced in power electronics

technology.