MedWeld 4000 Overview
1 - 24
Modified: 12/16/08
MedWeld 4000 Operator’s Guide
M-032116 Programs #T03300, #T02300 and #T02400
MFDC Control Component Descriptions
The MedWeld 4000 MFDC control has the following components:
•
Circuit breaker (page 1-8)
•
Isolation contactor (page 1-9)
•
Charging pack (Type 1 inverter only; see page 1-24) ,
•
Control transformer (page 1-9)
•
MFDC inverter (page 1-25) and
•
Weld processor (page 1-26).
Charging Pack
The charging pack is used to prevent damage to the inverter by
controlling the inrush of incoming power to the inverter's charging
capacitors.
Once the charging pack is activated, it remains activated until either an
inverter fault is generated, the charge request signal is deactivated
(Control Stop lost, ISOLATION CONTACTOR output deactivated on
an MF600 (without an isolation contactor after the inverter), or power is
removed from the MedWeld 4000).
If the inverter has discharged just before it is requested to close, the
inverter may delay activating the charging pack for up to 20 seconds.
The charging pack is external to the Type 1 inverter. The Type 2 inverter
includes the charging pack internally
For Type 1 (Medar) inverters, the charging pack will vary according to
the size of inverter:
•
Medar MF300:
The charging pack for the MF300 inverter is a
three-phase half-wave bridge rectifier. The rectifier module is
integrated into the MF300 inverter.
•
Medar MF600:
The charging pack for the MF600 consists of the
charging contactor and the mains contactor. The inverter controls
the operation of the charging contactor and the mains contactor. The
charging contactor is activated first (it charges the inverter's
capacitors through resistors). The inverter then closes the mains
contactor after the voltage has stabilized. The mains contactor
bypasses the charging resistors when it is pulled in. The mains
contactor provides the current capacity that the inverter requires
during firing.
The mains isolation contactor coil is driven through one of the
normally-open contacts on the charging contactor. This prevents
damage to the inverter in case of an I/O module failure.