Miller XMT 450 CC, Техническое руководство, Страница: 44 / 84

PRE-POWER CHECKS
TM-257 220 Page 40 XMT 450 CC/CV
10-4. IGBT Modules PM1, PM2
255 761-A
!
Read and follow safety
information in Section 10-1
before proceeding.
!
Wear an earth grounded
wrist strap when performing
pre-power and power off
checks. Remove wrist strap
before performing any
checks or procedures with
power applied to the ma-
chine.
IGBT Board
PC4 Or
PC5
Terminal
C1
Terminal
E2
Terminal
C2/E1
IGBT Module PM1 Or PM2
G1 (B1) G2 (B2)
PM2
PM1
.
Do not remove interconnecting
board PC2 to test the IGBT’s.
PM1 and PM2 are three terminal modules with two internal IGBT’s and two antiparallel diodes. Terminal C1 is the collector of the high side
IGBT. Terminal E2 is the emitter of the low side IGBT. Terminal C2/E1 is shared by both devices.
1. Visually inspect PM1 and PM2 for damage. If there is visual evidence of damage such as smoke/debris or found to be defective using this
procedure, replace both PM1 and PM2
2. Check function of IBGT’s in PM1 and PM2 with IGBT tester (MILLER Part No. 043 553). Disconnect gate lead Plug 3 from receptacle RC3
on Inverter Control board PC1. Connect tester to module terminals and gate lead plug as follows:
Module IGBT Tester Positive Lead − Red IGBT Tester Positive Lead − Black IGBT Tester − Gate
PM1 C1 E1 Plug 3-2
PM1 C2 E2 Plug 3-8
PM2 C1 E1 Plug 3-6
PM2 C2 E2 Plug 3-12
.
If an IGBT tester is not available an alternative test would be to use a DMM and perform the following steps. This test does not check
the function of IBGT’s in PM1 and PM2.
1. Check each module using the diode check on the DMM. Look for a diode drop of .2 to .9 VDC. across the following terminals:
Module Positive Meter Lead Negative Meter Lead
PM1 E1 C1
PM1 E2 C2
PM2 E1 C1
PM2 E2 C2
2. Disconnect gate lead plug (Plug 3) from receptacle RC3 on Inverter Control board PC1.
Check for gate resistance of 100k ohms. Place DMM in the ohms position.
Module Positive Meter Lead Negative Meter Lead
PM1 Plug 3-2 Plug 3-1
PM1 Plug 3-8 Plug 3-7
PM2 Plug 3-6 Plug 3-5
PM2 Plug 3-12 Plug 3-11