Catalogue - Dagu - #4

\( ES 6* SS

The first characteristic numeral indicates the degree of protection provided by the enclosure to persons and to the parts of the machine inside the enclosure. The second characteristic numeral indicates the degree of protection provided by the enclosure with respect to harmful effects due to ingress of water.

PROJECTS

Design of new motors is carried out using a "sheet" (Table 2). The customer shall have a copy of the datasheet along with any drawings enclosed with the offer. The sheet indicates the characteristic curve of the motor function as the following example.

STARTING OR BREAKING DYNAMIC

It can be useful to know the starting or braking dynamic of the motor. Starting time at a constant supply current is:

for:

ni = Maximum motor speed with constant current input (min¹) I = Input constant current (A) K_c = Torque constant (Nm/A)

I = Moment of inertia (m²kg), therefore calculated:

m = mass in kg

While the starting time at constant voltage supply is:

time costant =———

with 2.*^ac

R_tot = Total resistance (armature and power cable) in Q

I_tot = Total moment of inertia (armature and other moments

added) in m²kg Starting is accomplished at 3-=-5 t .

I Cmax 0__Imax Pa max__0___Pa max Pa max Va

Tab. 2

For every "x" function point, it is possible to read the following characteristics:

Cx = torque in the various load conditions nx = speed at the indicated torque Ix = current at the indicated torque

Pux = useful power of the motor at the indicated torque value Pax = electrical power input at the indicated torque value ETAx = efficiecy at the indicated torque

= dissipated power Vax = voltage at motor terminals

1,2 1

0,8 0,6 0,4 0,2 0

Pax Vax*

Speed during starting:

2 4 6

TORQUE (Nm)

10

DEGREES OF PROTECTION (IP)

-nx —Ix —Pux —Pax —ETAx

-Vax

by the letters "IP" followed by two numbers indicating conformity with the conditions shown in Table 1.

DHGa

motori elettrici