Page 15

background image


Fig. 1. Basic RAMM Connection Diagram

B. VOLTAGE FOLLOWING. All models can be controlled with an isolated analog refer-
ence voltage (0-6VDC) in lieu of the main speed potentiometer. The voltage is connected to P2
(+) and F-. The control output voltage will linearly follow the input voltage. The source im-
pedance of the input should be 10K ohms or less. The Min trim pot can be used to provide an
offset speed. If an offset is not required adjust the Min to 0+ or 0– speed as desired. The Max
trim pot is rendered inoperative in the voltage following mode. Use auxiliary trim pot to limit
the control range. If the input signal is not isolated, or is a current signal (4-20 MA), the RA-
SI240D) Signal Isolator must be used. It will allow direct connection to process controllers and

C. FUSING. The RAMM has provision for a built in AC line fuse and armature fuse. The AC
line fuse protects the control against catastrophic failure– if the fuse blows, the control is mis-
wired, the motor is shorted or grounded, or the RAMM control is defective. The armature fuse
provides overload protection for the motor and control. Choose the proper size armature fuse
by multiplying the maximum DC motor amps by 1.7. On domestic 240 Volt AC lines, separate
branch circuit protection for each line must be used. All fuses should be normal blow ceramic
3AG or ABC or equivalent.

1. AC Line Fuse is chosen according to the maximum rating of the control:
12 AMP fuse for all motors up to 3/4 HP-90V and 1 1/2 HP-180VDC.
25 AMP fuse for all motors 1 and 1 1/2 HP-90v and 2 and 3 HP-180VDC.

CAUTION: Do not bundle potentiometer connections (P1, P2, P3) and inhibit
connections (I1, I2) with AC line or motor wires.

CATUION: 1. The voltage feeding P


and F– must be isolated form the AC line.

Do not ground P


or F– to set up a zero ground reference.

2. Do not bundle signal wires to P


and F– with AC line motor

connections. If signal wires are over 18”, use shielded cables.