Filter
Top Products
Solid-State Starters — Troubleshooting guides and in-
formation pertaining to the operation of the solid-state starter
may be found in Fig. 44-46 and Table 11.
Attempt to solve the problem by using the following
preliminary checks before consulting the troubleshooting
table.
When the power is off:
• Inspect for physical damage and signs of arcing, overheat-
ing, etc.
• Is the wiring to the starter correct?
• Are all connections in the starter tight?
• Is the current feedback resistor properly adjusted and
installed?
• Is a heater coil installed in each leg of the motor?
• Is the control transformer fuse blown?
• Is the motor connected to the starter?
TESTING SILICON CONTROL RECTIFIERS IN
BENSHAW, INC. SOLID-STATE STARTERS — If a sili-
con control rectifier (SCR) is suspected of being defective,
use the following procedure as part of a general trouble-
shooting guide.
IMPORTANT: Before performing the SCR check be-
low, remove power from the starter and disconnect the
motor terminals T1, T2, and T3.
1. Connect ohmmeter across terminals L1 and T1. Resis-
tance reading should be greater than 50,000 ohms.
2. If reading is less than 50,000 ohms, remove connecting
bus heatsink between SCR3 and SCR6 and check anode
to cathode of SCR3 and SCR6 separately to determine
which device is defective. See Fig. 44. Replace defective
device and retest controller.
3. Repeat Steps 1 and 2 across terminals L2 and T2 for SCRs
2 and 5.
4. Repeat Steps 1 and 2 across terminals L3 and T3 for SCRs
1 and 4.
If the SCRs tested were not defective but the problem
still persists, refer to the following Steps 5 and 6.
5. Disconnect the SCR1 from the white gate and red cath-
ode wires on the AK control logic card. With an ohm-
meter set on Rx1, check between white and red wires.
Resistance should normally be between 8 and 20 ohms
average. Excessively high or low resistance may be
indicative of a defective logic card. Replace and retest.
6. Repeat Step 5 for SCR leads 2 through 6. Care should
be taken to ensure that the gate and cathode wires are
replaced exactly as they were: white wire to gate
(G1 through G6); red wire to cathode (K1 through K6).
Damage to the starter may result if wires are
reversed.
If the problem is still not resolved, consult the starter manu-
facturer for servicing.
LEGEND
SCR — Silicon Control Rectifier
Fig. 44 — Typical Benshaw, Inc. Solid-State
Starter (internal View)
81