ALLEN-BRADLEY ALLEN-BRADLEY BULLETIN 1336 PLUS MULTI - MOTORS APPLICATION NOTE # 1336S - 17 June 24, 1997 PURPOSE The purpose of this document is to provide guidelines for wiring and control schemes for the Bulletin 1336S AC Drive. This document is to be used as a suggestion only. Users must ensure that installations meet applicable codes and are suitable for the existing conditions. The Bulletin 1336S User Manual should be used as a reference to ensure that proper wire selection, routing and fusing guidelines are followed. WHAT THIS NOTE CONTAINS This note contains application assistance in running multiple motors from one 1336 PLUS drive. There are two distinct methods of operating the motors, having all motors start with the drive accelerating and decelerating as a unit or having each motor start and stop individually. Sizing the drive as well as interlocks required are different for each case. INTENDED AUDIENCE This application note is intended to be used by personnel familiar with the hardware components and programming procedure necessary to operate the Bulletin 1336S. WHERE IT IS USED The diagrams, parameter settings and auxiliary hardware used in this application note are designed to address specific issues in many different applications. Some changes by the User may be necessary to apply the concepts of this document to a specific application. TERMS AND DESCRIPTIONS Leakage Current - Is current in the motor circuit that is capacitive coupled to ground. Unshielded cable has approximately 5ma of leakage current/foot of cable. Shielded cable has approximately 15ma of leakage current/foot of cable. DESCRIPTION Unit Start/Stop When all the motors start and stop as one complete unit, the drive is sized by adding the full load currents of each of the motors and selecting the next larger drive. The amount of leakage current will very with cable type and distance. Typically increasing the drive by one rating is sufficient to handle this increased Faxback Document # 3037 Web location Http://WWW.AB.COM Page 1 of 4 ALLEN-BRADLEY current. To more closely size the drive for the Unit Start/Stop applications, use the formula below. Drive Rated Current = FLA M 1 + FLA M 2 + FLA M 3 + AMPS Leakage The motor contactors (if used) need to be interlocked with the run contact to ensure that a motor is not started when the drive is running. Figure 1 shows an example of this type of operation where all motors do not necessarily have to be operating all the time but they can not be started when the drive is operating. Stopping an individual motor is acceptable as long as not more than 50% of the motor load on the drive is removed at any one time. This type of operation is the least expensive method because of the reduced drive size. Individual Start/Stop When all or some of the motors must be started while other motors are operating from the drive, the drive must be sized for the locked rotor current of the motor(s) starting (LRAMX) as well as the full load current of the motors already in operation (FLAM2) plus the leakage current (AMPSLeakage). Drive Rated Current = LRA MX + FLA M 2 + FLA M 3 + AMPS Leakage Since the motors can be started or stopped at any time, interlocking is not required. Figure 2 shows an example of this type of operation. Again, the motors being stopped should not exceed 50% of the motor load current that is connected to the drive. The starting current can use the intermittent overload capability of the drive which is 150% of the rated output. As an example, if there are 5 motors with a full load current of 20 amps and a locked rotor current of 125 amps connected to a drive. The drive will require a full load rating of (20x5) or 100 amps. The intermittent rating would be (20x4)+125 or 205 amps. Instead of a 75 HP drive being used which has the full load rating of 106 amps, a 100 Hp drive with a rating of 138 amps is required to get the 205 amp intermittent rating. (138x1.5 = 207 amps). APPLICATION CONSIDERATION Since the drive is providing power to several motors, the drive can not be used as a motor overload device and separate overloads for each motor are required. With multiple motors, volts per hertz mode is recommended. PARAMETER SETTINGS Number 37 38 77 201 9 Group Setup Setup Feature Select Faults Control Select Name Overload Mode Overload Amps Speed Control Motor OL Fault Motor Control Value No Derate (total amps) No Control Disabled Fixed Boost Note: Par.48 [START BOOST], 83 [RUN BOOST] and 169 [BOOST SLOPE] in MOTOR CONTROL group need to be set for the values required by the load. Faxback Document # 3037 Web location Http://WWW.AB.COM Page 2 of 4 ALLEN-BRADLEY FIGURE 1MULTI-MOTOR WITH UNIT START 115V AC L1 R TB2 L2 S TB1 L3 GND T BULLETIN 1336PLUS 1 POT HIGH 2 POT LOW 3 POT/SIGNAL COMMON 4 5 0-10V INPUT 6 4-20MA INPUT 7 PULSE INPUT (-) 8 PULSE INPUT (+) 9 METER OUTPUT JUMPER J5 1-2 (4-20ma) 3-4 (0-10vdc) 10 CR1 PROGRAMMABLE 11 COMMON 12 CR2 RUN CONTACT 13 RUN CR2 CR3 FAULT 14 FAULT COMMON 15 CR3 NOT FAULT 16 CR4 ALARM 17 ALARM COMMON 18 115VAC INTERFACE TB3 RUN CR4 NOT ALARM TB3 19 INPUT 1 ENCODER B 31 20 STOP ENCODER A 32 21 COMMON ENCODER B 33 22 INPUT 3 ENCODER A 34 23 INPUT 4 ENC. +12V 35 24 INPUT 5 ENC. COMM 36 25 COMMON 26 INPUT 6 27 INPUT 7 RESET CR2 OFF ON OL M1 M1 CR2 OFF OL ON M2 M2 CR2 OFF OL ON Mx Mx CUSTOMER INTERLOCK 28 INPUT 8 29 COMMON 30 ENABLE INPUT MODE 2 U M1 Mx M2 V M2 W M3 M1 Faxback Document # 3037 Web location Http://WWW.AB.COM Page 3 of 4 ALLEN-BRADLEY FIGURE 2 MULTI-MOTOR WITH INDIVIDUAL START 115V AC L1 R TB2 L2 S TB1 L3 GND T BULLETIN 1336PLUS 1 POT HIGH 2 POT LOW 3 POT/SIGNAL COMMON 4 5 0-10V INPUT 6 4-20MA INPUT 7 PULSE INPUT (-) 8 PULSE INPUT (+) 9 METER OUTPUT 3-4 (0-10vdc) 10 CR1 PROGRAMMABLE 11 COMMON 12 CR2 RUN CONTACT 13 RUN CR2 CR3 FAULT 14 FAULT COMMON 15 CR3 NOT FAULT 16 CR4 ALARM 17 ALARM COMMON 18 CR4 NOT ALARM 115VAC INTERFACE TB3 RUN JUMPER J5 1-2 (4-20ma) TB3 19 INPUT 1 ENCODER B 31 20 STOP ENCODER A 32 21 COMMON ENCODER B 33 22 INPUT 3 ENCODER A 34 23 INPUT 4 ENC. +12V 35 24 INPUT 5 ENC. COMM 36 25 COMMON 26 INPUT 6 27 INPUT 7 RESET OFF OFF ON OL M1 OL ON M2 OFF OL ON Mx CUSTOMER INTERLOCK 28 INPUT 8 29 COMMON 30 ENABLE INPUT MODE 2 U M1 Mx M2 V M2 W M3 M1 Faxback Document # 3037 Web location Http://WWW.AB.COM Page 4 of 4