Literature
Technical Tips & FAQs
CEP7-EE_F/G/H Large Amp Overload Replacement Module
Question:
Can the large amp CEP7 overload relay (CT model) be repaired? What are the options?
Answer:
The CEP7-EE_F/G/H large amp current transformer overload relay model is designed in two pieces to facilitate replacement of the actual overload module. The cover can be removed to expose the mounting of the CT kit and a small frame size CEP7-EE_B-type overload relay.
In fact, page 6 of the CEP7-EE_F/G/H instruction sheet provides details of a specific part number CEP7-NREE_Z for the replacement small frame size overload relay.
| Part Number | Current Range | Overload Relay |
|---|---|---|
| CEP7-NREEHZ CEP7-NREEJZ |
30-150 A 40-200 A |
CEP7-EE_F |
| CEP7-NREEJZ CEP7-NREEKZ CEP7-NREELZ |
40-200 A 60-300 A 100-500 A |
CEP7-EE_G |
| CEP7-NREEMZ CEP7-NREENZ |
120-600 A 160-800 A |
CEP7-EE_H |
CEP7-NREE_Z represents the replacement overload portion inside the CEP7-EE_F/G/H device and is identical in production to part number CEP7-EECB; except for one feature - the dial.
- CEP7-NREE_Z - the low/high ranges on the dial are marked with the appropriate large amp values
- CEP7-EECB - the low/high ranges on the dial are marked with 1.0...5.0A
CEP7-EECB can be used as a replacement overload in conjunction with the CEP7-EE_F/G/F CT kit. However, the dial setting would need to be recalulated to match the applicable motor protection needed. The Sprecher + Schuh E-Catalog has some information in Section B that helps calculate the application's ratio and FLA.
Table for using Current Transformer with CEP7-EECB (range 1.0...5.0 amps) overload relay
| Current Setting | CT Ratio 150:5 Equivalent FLA |
CT Ratio 200:5 Equivalent FLA |
CT Ratio 300:5 Equivalent FLA |
CT Ratio 500:5 Equivalent FLA |
CT Ratio 600:5 Equivalent FLA |
CT Ratio 800:5 Equivalent FLA |
CT Ratio 1000:5 Equivalent FLA |
CT Ratio 1500:5 Equivalent FLA |
|---|---|---|---|---|---|---|---|---|
| 1.00 | 30 | 40 | 60 | 100 | 120 | 160 | 200 | 300 |
| 1.25 | 38 | 50 | 75 | 125 | 150 | 200 | 250 | 375 |
| 1.50 | 45 | 60 | 90 | 150 | 180 | 240 | 300 | 450 |
| 1.75 | 53 | 70 | 105 | 175 | 210 | 280 | 350 | 525 |
| 2.00 | 60 | 80 | 120 | 200 | 240 | 320 | 400 | 600 |
| 2.25 | 68 | 90 | 135 | 225 | 270 | 360 | 450 | 675 |
| 2.50 | 75 | 100 | 150 | 250 | 300 | 400 | 500 | 750 |
| 2.75 | 83 | 110 | 165 | 275 | 330 | 440 | 550 | 825 |
| 3.00 | 90 | 120 | 180 | 300 | 360 | 480 | 600 | 900 |
| 3.25 | 98 | 130 | 195 | 325 | 390 | 520 | 650 | 975 |
| 3.50 | 105 | 140 | 210 | 350 | 420 | 560 | 700 | 1050 |
| 3.75 | 113 | 150 | 225 | 375 | 450 | 600 | 750 | 1125 |
| 4.00 | 120 | 160 | 240 | 400 | 480 | 640 | 800 | 1200 |
How to read the table
- Current Setting - this is ultimately where you would set the FLA on the CEP7-EECB overload dial
- CT Ratio - this identifies which current transformer ratio is being used
Application Example
Motor rating of 125HP @ 460V...156 FLA
- 150:5 CT's would be just a bit too small, so the appropriate CT selection would be 200:5
- The calculation would appear as
Using the table - If our FLA were to have 150A, then the overload dial is to be set at 3.75. Since the example FLA is actually 156A, then the overload setting calculates to be set at 3.9. Proportionally it can be seen that 156A falling in between 150 (3.75)...160 (4.00) substantiates our calculation along with the 3.9A setting.
Therefore, in lieu of making a CEP7-NREE_Z selection, the CEP7-EECB, a readily available component, can be utilized as a replacement overload relay inside the large amp CEP7-EE_F/G/H overload relay, a significant savings over replacing the entire CEP7-EE_F/G/H.
Categories: Motor Protection
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