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6F3A4768
Each protection function is shown in below.
2.3.11.1 Current-related
protection
(1) AC over-current
OCA
When the output current exceeds the setting value, overcurrent is detected and an instantaneous trip
occurs.
Operation level is automatically set from CS_FRAME_SIZE, CS_EOUIP_CURR, AND CS_VOLT_RANK.
The operation level varies depending on the equipment and it is approx. 50 to 100% of the overload rating.
Manual setting for $CP_OCA is also possible.
(2) IGBT overcurrent
OCD
If IGBT malfunctions in the voltage type inverter and converter, two IGBTs in the same phase may turn on,
resulting in DC short-circuit. In this case, the charged capacitor is short-circuited with an IGBT element,
excessive current is flown to the IGBT element, and the gate signal of the IGBT becomes abnormal. This
condition is detected and an instantaneous trip occurs.
(3) Overload detection
OL5, OL20,OL_A
5-minute and 20-minute RMS computation of the output current is performed and when the predetermined
value is exceeded, activated.
5-minute RMS setting or 20-minute RMS setting is provided.
$CP_RMS_5
: 5-minute RMS protection
$CP_RMS_20 : 20-minute RMS protection
$CP_RMS_A5 : 5-minute RMS alarm
$CP_RMS_A20 : 20-minute RMS alarm
<Example> The equipment allows the following operation pattern. Therefore, the setting value is 5-minute
RMS when overload rated current (for example, 150%) continues for one minute after 100% continuous
operation.
Fig. 2.3.1 Allowable Overload Operation Pattern
$CP_RMS_5 =
$CP_RMS_20 =
(4) Current limit timer
CL_T,CL_TA
When the current limit is reached for the predetermined time period, CL_T is detected.
The standard setting is CL = 60.0 (s).
This function provides an alarm. A current limit alarm (CL_TA) is detected at TIME_CL x 80%.
(5) Low frequency overload STALL (TMdrive-30)
This is detected when large load is applied at low frequency.
(1
2
x 4 + 1.5
2
x 1 ) / 5 = 1.118 =
111.8
%
(1
2
x 19 + 1.5
2
x 1 ) / 5 = 1.03 =
103.1
%
100%
150%
4 minutes
1 minute
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