SAMCO-vm05 Series (SHF/SPF, SBT)

Protection Functions

Protection functions Description Indication
Overcurrent limiting (Anti-breakdown) When the current exceeds the value set by Cd043, the frequency curves are adjusted to limit the increase in current.


After the output current reaches the setting for Cd043 during acceleration, the frequency increases at a slower rate for a while to accelerate the motor within the current limit, preventing breakdown from occurring.

Constant power operation:

When the output current reaches the setting for Cd043 due to an overload during constant power operation, the frequency is reduced to keep the output current below the setting. When the overload is removed, the frequency returns to its previous setting.

Overvoltage prevention When the energy regenerated during deceleration of the motor exceeds the dissipation capacity of the brake resistor, raising the DC voltage of the inverter, the drive frequency stops decreasing and actually increases as necessary to prevent an over-voltage trip. After the regenerated energy decreases, deceleration is continued at a slower rate. Su
Overcurrent shutdown When a current exceeding the allowable current range of the inverter is input, the protection circuit activates and stops the inverter. oCA, oCn, oCd
Overvoltage shutdown When the inverter-DC link voltage exceeds the specified voltage due to excessive regenerated energy, a protection circuit is activated to stop the inverter. ouA, oun, oud
Protection against undervoltage
(momentary power failure)
When the DC voltage falls below the specified value due to an abnormal power supply voltage, the inverter stops operating. LuR, Lun, Lud
Overload shutdown (motor electrothermal protector) Overloading and overheating of the motor during low speed operation are detected by the electrothermal protector to stop the inverter. Different values can be specified to trip electrothermal protector depending on the type, rated current, etc. of the motor. oLA, oLn, oLd
Overload shutdown (inverter thermal protector) The inverter stops operating when a current greater than the current rating of the inverter flows for one second or longer. oCPR, oCPn, oCPd
Protection against radiator fin overheat A warning (tH) is issued at a temperature 10q[C below the abnormal radiator fin temperature (oH) when the ambient temperature rises sharply or the cooling fan stops. If it continues to rise further and exceeds the abnormal radiator fin temperature (oH), the protection function stops the inverter. The abnormal radiator fin temperature (oH) differs depending upon the output frequency and output current. This function also stops the inverter when the main switching device (power module) is overheating. This function is released when the temperature decreases to more than 10q[C below the abnormal radiator fin temperature (oH). tH, oH, oCH
Brake resistor
overheating protection
As the regenerative energy of the motor increases, and the allowable brake resistor value (%ED) is exceeded, the brake resistor becomes temporarily unusable due to overheating protection. By letting the brake resistor cool down, it becomes usable again. dboH
Overload prevention alarm The inverter stops operating if the motor is unable to accelerate or decelerate because the motor load is excessive or the setting of Cd043 (output current limiting function) is too low. ACEr, dCEr, CnEr
External thermal protection An external thermal protector can be attached to a motor. By inputting this signal to the ES control signal terminal, the inverter can be set to stop when the thermal protector is activated. ES
CPU abnormality If excessive external electrical noise or other disturbances lead to a malfunction of the CPU, connection failure of an option board, or internal memory abnormality, the inverter stops operating. AL1qAL10
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