Specications Information and Repair Parts Manual 3890-99 & 3891-99
3890-254-00 1 2/2015
Please read and save this Repair Parts Manual. Read this manual and the General Operating Instructions carefully before attempting to assemble, install, operate
or maintain the product described. Protect yourself and others by observing all safety information. The Safety Instructions are contained in the General Operating
Instructions. Failure to comply with the safety instructions accompanying this product could result in personal injury and/or property damage! Retain instructions
for future reference. AMT reserves the right to discontinue any model or change specications at any time without incurring any obligation.
©2015 AMT Pump Company, A Subsidiary of The Gorman-Rupp Company, All Rights Reserved.
Periodic maintenance and inspection is required on all pumps to ensure proper operation. Unit must be clear of debris and sediment. Inspect for leaks and loose bolts. Failure to do so
voids warranty.
Pump Pedestal Adapters
Refer to pump manual 1808-635-00 for General Operating and Safety Instructions.
Find desired pump speed in accordance with the performance chart.
Select the driver with the proper RPM and corresponding pulley sizes.
ASSEMBLY
Assemble bearing housing (Ref. No. 2) to pump (See pump manual
“Maintenance”).
NOTE: The hardware (see pump manual “Repair Parts List”) supplied with the
pump head is used to attach the pump to the pedestal.
NOTE: For proper selection of pump head unit, contact dealer where pedestal
was purchased.
ROTATION MODEL 3890-99
(KEYED SHAFT MODEL)
Rotation will depend on pump being driven. Check before attempting to install
unit in service (see pump manual).
ROTATION MODEL 3891-99
(THREADED SHAFT MODEL)
This unit can only be used with counterclockwise rotation (CCW) facing the
threaded shaft. Use only with pumps that turn CCW when facing front of pump
(shaft end of motor). A vial containing a removable grade of thread sealant
(Ref. No. †) is included with the 3891-99 pedestal. This is to be applied to the
threaded end of the shaft (Ref. No. 4) just before installing impeller for last time
(see pump manual “Shim Adjustment”). This will help control the impeller from
loosening in the event that the unit is started in the wrong direction (i.e., as in
3-phase operation, etc.).
Failure to follow the above information may cause impeller to unscrew
and damage pump head, cause property damage and/or personal injury.
DESCRIPTION
MODEL 3891-99
Used with pumps that require a NEMA 56J Face with threaded shaft. Equipped with a stainless steel shaft, which extends 2-3/8” from mounting face. 5/8”
diameter threaded 11/16” from end of shaft with 7/16-20 UNF-2A threads. Opposite end is 3/4” diameter with a keyway.
MODEL 3890-99
Used with pumps that require a NEMA 56C Face with keyed shaft. The unique design of the pump head is such that no part of the pump pedestal adapter
(including shaft) normally makes contact with the uid being pumped. This allows the pump pedestal adapter for both type 316 stainless steel and bronze pumps
to be one unit made of cast iron (steel shaft).
MODELS 3891-99 AND 3890-99
With pump pedestal attached, these pumps can be installed with direct-coupling drive or pulley drive and by electric motor or belt driven with gasoline engines.
Pully Diameter*
Pump Speed RPM Motor Speed Motor Pump
1725 1725 RPM 3” 3”
3450 RPM 2-1/2” 5”
2300 1725 RPM 4” 3”
3450 RPM 3” 4-1/2”
2800 1725 RPM 4” 2-1/2”
3450 RPM 2-1/2” 3”
3450 1725 RPM 6” 3”
3450 RPM 3” 3”
* All A Section, single groove, over 1 HP double groove pulleys/
belts should be used.
PULLEY DRIVE CHART
