Instruction Manual

Two relays for monitoring the status of the frequency converter are located on the power card. These are programmable through parameter group E-##. The
relays are Form C, meaning it has one normally open contact and one normally closed contact on a single throw. The contacts of the relay are rated for a maximum
load of 240 VAC at 2 Amps resistance.
The logic circuitry on the control card allow for the addition of option modules for synchronising control, serial communications, additional relays, the cascade
pump controller, or custom operating software.
3.2.2 Logic to Power Interface
The logic to power interface isolates the high voltage components of the power section from the low voltage signals of the logic section. The interface section
consists of the power card and gate drive card.
Much of the fault processing for output short circuit and earth fault conditions is handled by the control card. The power card provides conditioning of these
signals. Scaling of current feedback and voltage feedback is accomplished by the control card.
The power card contains a switch mode power supply (SMPS) which provides the unit with 24 VDC, +18 VDC, –18 VDC and 5 VDC operating voltage. The logic and
interface circuitry is powered by the SMPS. The SMPS is supplied by the DC bus voltage. The frequency converters can be purchased with an optional secondary
SMPS which is powered from a customer supplied 24 VDC source. This secondary SMPS provides power to the logic circuitry with main input disconnected. It can
keep units with communication options live on a network when the frequency converter is not powered from the mains.
Circuitry for controlling the speed of the cooling fans is also provided on the power card.
The gate frequency converter signals from the control card to the output transistors (IGBTs) are isolated and buffered on the gate drive card. In units that have
the dynamic brake option, the driver circuits for the brake transistors are also located on this card.
High Power Service Manual for Unit Sizes 6x
33
3