TM 5-3895-374-24-1
Options
ALTIVAR 0,75 to 30 kW
Special case braking resistance thermal protection
The standard resistance does not have thermal protection
The elements making it up can, without damage, reach temperatures higher than the steady
state temperature of 300°C noted on page 66
The ALTIVAR ATV-452, however, fitted with a braking option, enables the resistance to be
protected against overheating, by using a normally closed thermocontact or overload relay
This protection can be necessary in the following cases
- utilization of resistances of a kind whose insulation risks being damaged or destroyed if heating
is abnormally high,
- applications in which higher or more frequent braking than planned, can prove dangerous for
the installation or the driven machine
Choice of thermocontact
- minimum DC electrical characteristics on resistive load 10V - 5mA,
- tripping temperature to be determined according to the resistance used and the selected
location
EXAMPLE: standardized resistance Choose a 2600 C thermocontact and, attach it to the upper
metal band joining the two elements on the right
Choice of thermal overload relay
Calculate the thermal overload relay rating using the formula I = P , in which
R
- P = rated power of the resistance,
- R = ohmic value of the resisitance
Connect the thermal overload relay's N/C contact to terminals PY-PZ
Initial setting up
The initial setting up of the braking option needs no adjusting
After checking the connections and perhaps adjusting the speed controller settings (see p 38
onwards), the ALTIVAR can be switched on
Should there be any doubt as to the braking power, proceed in the following manner
- preset a deceleration ramp longer then the required braking time,
- start up the machine and carry out successive braking operations, gradually reducing the ramp
time until the final adjustment is reached, making sure that the braking cycles are identical to
those for real use
Maintenance
In the event of overbraking, the speed controller may display the following codes
0br Deceleration ramp not followed
Increase the
0bF Capacitor overvoltage owing to excessive
deceleration time
braking or a driving load
(page 3-222)
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